If you are going to fish Harriet, I would not recommend camping at the lake with your family. It is usually crowded this time of year and you might end up with neighbors you don't like. The lake gets a little boisterous at times. There is great camping nearby, however.
I camped on the upper Clackamas last weekend and my neighbors had more guns and ammo than a small militia. Even an assault-rifle. I thought I was in a Bosnian warzone. They quieted down at night and all was well. I caught and released a bunch of small brookies and cuts.