I would recommend Lyell for an easy trip for a family - you can camp and spend days fishing up and down, and taking pictures. But the bears will haunt you at night.
At the end of August I will be doing Tuolumne to Happy Isles, via Cathedral Lakes, Sunrise HSC, Clouds Rest and on down to the valley. Am doing Half Dome at Sunrise TONIGHT. I love living in the shadow of the park!