I just got back froma long weekend in grenoble, not much bouldering but the route climbing is second to none, cliffs and routes everywere, good biking, and grenoble itself is a wonderfull city, and that saying something, (i hate cities)
I seem to remeber it being under an hour from lyon, so well worth the trip, depends on what part of lyon you will be at but I reccon you could get to some of the areas in a bout 30/40 minutes drive
good luck