We advise you leave Chamonix at 6am. Take the direction of Megève, then Flumet to atack the 1st pass - Col des Aravis. The descent is quiet until Thones, then climb the Col de Bluffy (very easy). Then descend to Lake Annecy. 40km to complete the tour.
You can return by the same way, but you also have two other options.
1 . Arriving at Saint Jean de Sixt, turn left to climb the Col de la Colombiere then Cluses Sallanches and Chamonix. The difficulty is approximately the same.
2. Arriving at Saint Jean de Sixt, turn left and follow Bonneville. The road is longer but there is less difference in height.
Chamonix - Les Houches - Servoz - Le Fayet - Megève - Flumet - Col des Aravis (1486m) - La Clusaz - St Jean de Sixt - Thones - Col de Bluffy - Talloires - Tour du Lac d'Annecy - Col de Bluffy - return is the same ... - Fayet - Servoz - Les Houches - Chamonix
245 km and 3600 m elevation.