Some idea for your routes between Italy, Austria and Slovenia.

Today I would like suggest you this cycling path that joint Italy and Austria.
The cycling holiday can start from Sillian in the Tyrol region. Can go to this area with bike on train service.
On ride the Puster Valley to Lienz and after to Spittal, famous for his Porcia castle. You are in Carinthia where you can ride to the Paternion castle and Villach. Crossing the Drava you can ride along the Faaker See and Worthersee lakes.
The travel continue to the Lavamund village at the border with the Slovenia.

The distance of this path is around 250km and are good also for children.
Good accommodations are present along this route.

For a fee our company can arrange customized pick up and bike collecting also in Austria and Slovenia countries.