I would absolutely encourage you to visit Slovenia, @discovereurovelo. It's not called the cycling paradise for nothing, people there are absolutely friendly and the roads for the most part are calm enough for cycling.

As far as I know there are two major bike paths, one of them is the Slovenian part of Euro 9 that goes from Maribor down to the Mediteranean and the other one is the Drava river trail, that follows the Drava in it's length, but trails and endless.

The only drawback is that it's hilly, it goes from the normal ups and downs to the insanity of the Alps.