In Romania, it's best you visit Bran castle, do some hiking in the mountains there if you're interested and then go elsewhere since there doesn't seem to be any real monasteries worth visiting. In Romania, I’m assuming you mean Bran Castle when you say Dracula castle. This is located near Brasovand is around 3 hours from Bucharest. You could stay in the http://www.predelut.ro/en/ bed and breakfast in the Bran area or use Brasov as a base since it has vegan options: http://www.happycow.net/europe/romania/brasov/
The Bran castle from a distance looks like this,
There is also the Rasnov fortress 15km from Bran towards Brasov where there is some hiking that you could do. Another place that’s supposed to be worth seeing in Peles Castle near Sinaia 50km from Bran.
[From Brasov, you'd have to go back to Bucharest to go to Macedonia via Bulgaria and Bucharest to Sofia is at least 7 hours. If this is too long, you might want to consider using trains/public transport in Romania and take a train to Sofia (preferably at night to save time) and then rent a car since distance would be shorter from here onwards.]
The most interesting place along your route in Bulgaria I found was the UNESCO-classified Rila Monastery (photo below) in the western mountain area. In the same area for some natural beauty and hiking you could go to Mount Ezeren for a fantastic view of Seven Rila Lakes. Rila is a 2-hour drive from Sofia.
Here's some information I found on a website:
The Seven Lakes are close to the Rila Monastery, Malyovitsa and the Skakavitsa Waterfalls areas, which gives numerous options for planning a few days walking route. Most of the visitors drive, take taxi or a shuttle from Sapareva Banya – a village in the foot of the mountains, 70 kilometres away from Sofia, famous with the hottest thermal geyser on the Balkans (103 degrees). The road from the village leads to Pionerska Hut (1585 m.), from where a chair lift operates all the year round and takes visitors up to 2150 m. elevation. Near the top station of the lift is build Rila Lakes Hut – more hotel-like accommodation.
From this point it is possible to do a few hours walk around the lakes and go back – usually up to the Lakes Mount, placed between The Teardrop and The Eye lakes. Unfortunately too many people take this option in summer and the crowds may spoil the great views. There is a few other huts in the area, opened for visitors – these include the old Seven Lakes Hut, about an hour away from the lift station (offers rustic accommodation), Lovna and Skakavitsa huts and Ivan Vazov Hut, located high in the mountains and separated by the Seven Lakes cirque by Otovica Ridge, which is the only place where all the lakes are seen under our feet.
For accommodation: http://www.lonelyplanet.com/bulgaria/rila-and-pirin-mountains/rila-monastery/hotels
For food, Bulgaria has a lot of salads so you might have to settle for that or make something using salads and beetroot for example. I read another blog where someone mentioned a restaurant where they knew what a vegan meal was and even had vegan brownies apparently. Unfortunately, there was no name! You might find it if you ask around. One thing is for sure, the monastery seems really amazing.
In Bulgaria, there is no accommodation in the the Rila monastery itself. You'd have to stay in one of the many hotels that cater to travellers visiting this monastery and the Rila Seven Lakes in the nearby mountains.
From there you could move on to Macedonia. A friend on mine went to Prilep to visit the ruins of Marko's tower fortress with sweeping views over the city and countryside and I thought it looked amazing. Near Prilep is the city of Krushevo, the highest village in the country with interesting architecture. 2 hours from Prilep is UNESCO-classified Ohrid for its history and nature (there is a huge lake part of which is in Albania). There are plenty churches here. Roman amphitheater, Church of St Sophia and St Clement, Tsar Samoil's fortress and Ohrid's marketplace are some of the places to visit. Daily ferries takes passengers from the city square to the nearby Monastery of St Naum. Originally built in the 10th century, the monastery is home to the body of Byzantine St Naum, who is known to have cured patients of mental illnesses.
http://biljanasykesyoga.com/retreats.aspx?cid=880&l=23 I'm not sure this place is open yet but you could try and contact them.
There is a restaurant in a hotel called Salida in Prilep at this address Orde Copela BB, Prilep. It has vegetarian options but not sure about vegan. Ohrid has plenty of restaurants so they must have vegetarian/vegan options. There are beetroot soups and salad items all over this region although I'm sure you'll need more than that!
In Ohrid, Macedonia there is a beautiful orthodox church/monastery called Sv Jovan Kaneo by the lake. Ohrid has 365 churches and is a UNESCO site.
In Montenegro, the most interesting places to visit are close to each other. They are 7 hours from Macedonia. Kotor is located on the Boka Bay and if you hike up to Njegos Mausoleum in the Lovcen national park, you will get great views not only of the bay itself but of the neighbouring mountains. You could also visit Perast, 10 km from Kotor. You should be able to do all this in a day and a half and make your way to Sveti Stefan, another interesting site in Montenegro.
There is supposed to be a cafe and juice bar in Budva, Montenegro that has vegan options on Vranjak 13 in the Old Town.
From here, Vlora, Albania is a 5h30 drive. In Albania, the drive from Vlora to Llogara and then through Dhermi and Himare to Saranda is supposed to be beautiful. Since you like castles, Gjirokaster is a UNESCO site that you might like. On the way back to Tirana, if you have time you might want to stop at Berat, medieval UNESCO-listed town. Along the southern coast from Vlora to Saranda, there are places that you can hike and paraglide in.
I don't seem to be able to find any vegan options in these two places but in Tirana, this is what I found: http://www.happycow.net/europe/albania/tirana/
Back in Vienna, some of the noteworthy things to do are as follows. Before you read further, here is a panorama of Vienna for you to savour.
Domkirche St. Stephan - Dating from the 12th century, St. Stephan's Cathedral is the grandest such edifice inAustria. The basilica is filled with such treasures as the carved wooden Wiener Neustadt altarpiece and the tomb of Emperor Frederick III. To cap your visit, climb its south tower with its 343 spiral steps for the most panoramic view in all of Vienna.
After a tour of the cathedral, you can stroll up the pedestrian-only Kärntnerstrasse, the main shopping street of Vienna. Kärntnerstrasse will lead you to the imposing Staatsoper with its elegant arcades, this is Austria's leading opera house. Some of the world's greatest music -- often from fabled Austrian composers of yesterday -- is presented here in this French Renaissance-style building, one of the first of the great public buildings to be built here. This is a great place to attend an opera performance.
With the time remaining in your day, you can head for the Hofburg Palace Complex. Depending on where you are in the city, the U-Bahn to Stephansplatz can take you here, as well as the U-Bahn to Herrengasse or Mariahilferstrasse.
This was the winter palace of the Habsburgs, who ruled over much ofEuropefrom here. There is so much to see and do that you can't take it all in 1 day. But the main attractions are Albertina, Augustinerkirche, Kaiserappartments (Imperial Apartments), and the magnificent Schatzkammer (Imperial Treasury).
Within the complex, try to visit the:
Albertina - Originally part of an Augustinian monastery, this 18th-century palace housesAustria's celebrated Collection of Graphic Arts. More than a million sheets -- old masters' drawings, engravings, and architectural designs -- illustrate this development of graphic arts since the 1300s. The highlight of the collection is a series of drawings and engravings by Dürer.
Augustinerkirche - The 14th century Church of the Augustinians, built within the Hofburg complex, was the parish church for the imperial Habsburgs. In 1748 the baroque interior decoration and all the original Gothic architectural details were removed. The highlight of the church today is the elaborate tomb of the Archduchess Maria Christina, favorite daughter of Maria Theresa. The Italian sculptor, Canova, slaved over the white marble mausoleum from 1805 to 1809.
Kaiserappartements - The Imperial Apartments are on the first floor of the Chancellery Wing. Actually, there are 2,600 rooms in the Hofburg, but only 20 are open to visitors. The emperors, along with their wives and children, lived here. The apartments are richly decorated, the highlight being the Imperial Silver and Porcelain collections. Six rooms are devoted to the tragic empress known as "Sissi."
Since the Hofburg complex is so vast, you may want to head for the Café Tirolerhof for coffee and snacks. One specialty that will get you going again is a coffee known as Maria Theresia. This is a large cup of mocha flavored with apricot liqueur and topped with whipped cream.
The grandest attraction at the Hofburg is the:
Schatzkammer - The Imperial Treasury contains all those glittering Habsburg jewels, the loot of a once-great empire, including the crowns of the Holy Roman and Austrian empires. The greatest treasure is the Imperial Crown, dating from 962.
Spanische Reitschule - The Spanish Riding school is where the famed Lipizzaner stallions strut their stuff, a show that has been going on for 4 centuries (but not with the same horses, of course). The equine performers are viewed as the finest in the world, their feats of dressage unequaled. The tails and manes of the stallions are plaited with gold ribbons, and they dance the polka, the gavotte, the quadrille, and the slow waltz (we kid you not).
Burgkapelle - The home of the Vienna Boys' Choir is in the Hofmusikkapelle, part of the Burgkapelle, a Gothic chapel dating from 1447. Seeing a performance can be a bit tricky. The singing boys are often touring the world.
Ringstrasse - As night falls over Vienna, take a streetcar ride around the entire Ringstrasse or circle of boulevards that enclose the old city of Vienna. The tram follows the route of the medieval fortifications.
On day two you can go to Schönbrunn Palace - This was the baroque summer palace of the Habsburgs. Built between 1696 and 1730, it contains a staggering 1,441 rooms. Empress Maria Theresa and her 16 children left the greatest impact on the palace. Franz Josef I, who was born in the palace and reigned for 68 years, was the last emperor to live here. The greatest attraction are the stunning State Apartments, followed by the Gloriette, a marble summerhouse, and the palace's Imperial Gardens.
Head up to the Glorietta on the hill for a view of the castle.
If you choose to do less than this or skip one of the castles, you could then do a trip to Salzburg.
In Salzburg the must sees are the Mirabellgarten, Mozart's birthplace Getreidegasse, Festung Hohensalzburg, an amazing medieval fortress dominating the city (accessible by funicular or on foot) and Salzburg Festival House where some really good free musical performances are given.