Hey there! Oh wow, Tatvan and Bitlis, that's such an awesome choice, you're going to have an incredible time! I totally get feeling overwhelmed, but honestly, it's a pretty chill area once you're there.
For absolute must-dos, you absolutely, absolutely have to make your way up to Nemrut Crater Lake. No, not the one with the statues, a different Nemrut! It's just outside Tatvan and it's seriously mind-blowing. You've got these stunning crater lakes, some hot, some cold, and the views are just insane. If you can manage it for sunrise or sunset, it's just magical. It feels really off the beaten path and not super touristy, which sounds like what you're after.
Another spot that blew me away was the Ahlat Seljuk Cemetery. It's not like any cemetery you've ever seen, it's got these massive, ancient Seljuk gravestones that are more like monuments. It's incredibly atmospheric and full of history. Really unique and gives you a good sense of the region's past. And of course, just walking around Bitlis town itself, seeing the castle ruins perched up there, even if you don't go inside, it's a cool landmark. The views of Lake Van from Tatvan are also just stunning, definitely take some time to just chill by the lake.
Food-wise, you HAVE to try a proper Van breakfast. Even though it's technically Van, it's super popular and available everywhere in the region. Think tons of little dishes, local cheeses, honey, olives, fresh bread... it's a feast! For dinner, definitely hunt down some local kebabs or köfte. The meat in that region is just incredible. Ask locals for their favorite little lokantas, that's where you'll find the real gems.
Getting around is pretty straightforward. Within Tatvan or Bitlis, you can walk a lot, especially in the town centers. For getting between Tatvan and Bitlis, or up to Nemrut or Ahlat, dolmuşes (those shared minibuses) are your best friend. They're super cheap and run frequently. Just ask around for the dolmuş stops. Taxis are also available if you're going somewhere a bit more remote or want convenience, but the dolmuş system works great for most places.
Honestly, just soak it all in, talk to the locals if you can, and don't be afraid to just wander. You're going to love it! Have an amazing trip!