Romania is quite simple now: G space for ground to FL 105 less airways which are class C and TMA Bucharest which is A, FL105 to FL195 is class C less TMA Bucharest, and class A above - so you can do VFR ground to FL195.
You'll have to enter and leave the country at an international airport with customs, so Kogalniceanu LRCK is the choice, then you can go to Tuzla LRTZ for seaside fun. Flying the coastline is almost all G space, less the 2 CTRs and some LRDs, check NOTAMs for activation. You'll pass over Danube Delta and big lakes, great views are guaranteed!
I don't know about AVGAS & prices, will ask come back ASAP.