We went to the Alps by van for almost three weeks this year. Morzine, Verbier, Pila (for a day) and Bourg St Maurice/Les Arcs.
It was amazing. We hired an apartment in Morzine, hostels in the other places (and a few days with a bikeholiday company).
The great thing about driving down is that you can visit a few places – and you can take the entire contents of your garage with you of course.
But from the places I’ve been Les Arcs might suit you best because it has a massive variety of trails accessed by a very extensive lift system. Guiding would be a big advantage – and I got the impression it wouldn’t be too hard to sort that out independently.
Verbier is also amazing, as long as you’re not put off by steepness.
Get that Mountain Biking Europe book published by Footprint.