I'd wait until the first week of July to go to Les Arcs as the lifts won't be open in June.
Nancroix – Stunning location but not as practical as the others.
Llandry – Nice and peaceful with a short ride up the valley to the funicular in BSM every morning.
Le Versoyen – Definitely the most practical site with bars/shops/supermarket/amenities all close by plus you can ride well into the evening using the funicular and free bus without worrying about a long climb home at the end of the day. We stopped in BSM last time and only used the car once all week for a trip up to Col de L'Iseran.