There's good wind-surfing all along that part of the Med - we used to go, years ago, to Cavalaire, and at the eastern end of the beach there were many places hiring out boards and giving instruction. Inland, from Cavalaire, too, there are lots of forest roads which would be great for mountain biking. There are a few sites there - Selection Camping at the right end of the beach, Cros du Mouton - up in the hills, so you could bike down into town (and walk back up???) or Camping de la Baie which is right in the middle of town. Cavalaire tends to be just a bit quieter, than the Frejus/St Raphael/St Tropez sites, being 'off the main drag' with less traffic. We have friends who live nearby in La Croix Valmer - and it's a lovely rather under-rated part of the Mediterranean coast.