If you have transport and can get to Samoens, there is some excellent XC riding from there (was out there a couple of weeks ago). Get an MTB map from the tourist office (and probably the IGN 1:25k map as well as not everything is clearly waymarked). Samoens is very much open for business; Bar La Savoie in the main square does decent food all day.
One option is to try the climb up the road to Pont du Dedain then offroad to Lac du Gers (took us 1h 15 I think); from Roux you drop back into Samoens entirely on singletrack – a classic.
On the Joux Plan side, the route that climbs up via Les Allemands, across the hill and down the trail marked as “black 61” on the map is most excellent. The red one off the main Joux Plan road also very good (#50 I think) – you can pick that up at the top of the col, or about 1100m where a track goes straight on from a right hand hairpin (it’s obvious from the MTB map as a couple of routes use the track).
Also some good stuff down from Les Esserts into Morillon.
On the road, Morzine/ Col d’Encrinaz/ Pont du Gets/ minor road into Taninges/ Samoens/ Col du Joux Plan/ Morzine is a great circuit.
The Col du Ramaz is also great (from Mieussy via Sommand to Praz du Lys); you could go main road through Les Gets, minor road at Pont du Gets to Taninges, Mieussy, Ramaz, then back over Encrinaz to Morzine.
Final road option is Vallee Vert from St Jean d’Aups – lots of quiet roads in that area.