If you want to camp after Labor Day but before Haloween, Chena Lakes campground is wonderful. Generally, there is no one else camping there, or at least you can get out of sight of anyone else that is there. There is great fishing on both the lake and river and the whole park is very well maintained and beautiful. The best part is that you will pretty much have the whole park to yourself!
Around 48 miles down the Richardson Highway, to mile marker 305.2, is a military recreation camp called Birch Lake. If you are active or retired military, check it out. The lake is stocked with rainbow trout, king and silver salmon, grayling, and arctic char.