Just seen that you will be in Doussard. The ride into Annecy (or up to Ugine) will be easy enough for wife (and kids?) to join you. My best recommendation is that you don't miss the Cote de Puget. Ride the railway path as far as St Eustache, where you take the slip ramp on the left where you see the building marked "Marine Services" and take the little road up through the estate to La Chapelle St Maurice. Then turn around and enjoy the spectacular lake views on your way back down to Doussard. There and back is about 26 miles from Doussard. As to the circuit of the lake, I made that 25.1 miles from Doussard. Both quite possible before breakfast! The climb up to the Col de la Forclaz (the difficult way, via Vesonne and Montmin) is also very close by from Doussard, and the view from the summit is not to be missed. (Also take the missus up there to eat at the Chalet la Pricaz, just below the paragliding take off point).