We rode to Hungary last year via; France, Italy, Slovenia, Croatia then back up through Slovenia into Hungary then back through Austria, Czech Republic, Germay and France.
I thought Hungary was a a bit boring, but we only rode across the the North East part of the country as we headed for Budapest, so probaby didn't see the best of it.
Slovenia was the biggest surprise of the trip. The scenery and roads up through the Julian Alps were stunning. Typical winding alpine roads lead up to narrow un-made tracks which branch off the roads and are perfect on a big traily. One particular road lead to a cafe at the highest point on a mountain pass above cloud level. We sat outside on a bench drinking coffee while small fluffy clouds drifted below....magic.
It was also a very cheap country to visit. We had a full service and a new rear tyre on the GS for under £200 in Ljubiana at an official BMW dealer.