Yes, along the coast is a great idea. Also try to stay above 5,000 ft.
Avoid the basins between the west coast mountain ranges and the Rockies.
The Great Lakes area can be nice most of the summer. And the Appalacian's or east coast.
Believe it or not, but everything I've experienced and seen on forums is that the campgrounds on the east coast are more crowded than the west coast in the summer. A lot more families and kids out of school.
Try to make a plan, and hopefully be able to reserve Memorial Day, 4th of July and Labor Day weekends. Reservations are not that essential in may places the rest of the year, if you are willing to dry camp a few days.
Every year about this time, those of us from Texas see many threads about the best places to camp in Texas in the summer.
For most Texans, the best place to be in the summer is Colorado.
