If you make it to the state of Maine, I cannot promote the State Park system here enough. Most of them don't have hook ups, but most do have hot showers and flushing toilets.
I will tell you that they ALL have incredible scenery, and are immaculately maintained. Staff are great, and very attentive.
Best part? Sites are $18.50 for out of state residents, $16.50 for instate. You need to call 48 hours in advance to reserve, or you can just show up that morning, but no guarantees.
I tell you, you won't regret it.