Family road trip - south-central Europe

We’re planning a Europe road trip with our young family (w/ 2 kids 1&3). Looking to spend time around the south of central Europe but not fixated on any particular area. We’re adventure people but feel with the kids may be best suited to small/medium type towns, especially with a car for flexibility. We’d probably spend most of the days wondering about, maybe a lunch here and there but I’d imagine most of the time at the apartment cooking our own meals.

Thinking flying in/out of Milan, going up through France, lux, south/west Germany, Switzerland & northern Italy. Is there particular places which people would recommend visiting ? Probably looking to spend approx 4-5 night in each place, 2 months total from early-aug to late-sep. Tips or ideas appreciated !