I've always liked Tuff Campground. It's small so there isn't a lot of people, plus it's right next to Rock Creek so you don't have to go to far to drop in a line. It's on the east side of 395 from Tom's Place and it's kinda centrally located to the Bishop/Mammoth stretch of 395.
Late season, especially after Labor Day, I like to camp down in Devil's Postpile along the Middle Fork of the San Joaquin. The canyon offers some shelter from winds and lots of good fishing for 3 kinds of trout (some say 4, but I don't believe stories about Goldens in the river) - lakes or river. I always see a lot of bears and deer other critters. If you're into mountain biking, they have a couple of ski lifts operating on the mountain. It's a nice place to hike around - Rainbow Falls can be spectacular in a wet year. Plus, town isn't too far away.