We stayed last summer at Timberland Acres near Trenton, MA. Close to Acadia NP, and about a half hour to Bar Harbor. Made a good base for exploring.
Timberland Acres RV Park 57 Bar Harbor Rd, Trenton, ME 04605 207 667 3600
info@timberlandacresrvpark.com
We really liked Hopewell Rocks in New Brunswick, but couldn't get reservations in Bay of Fundy Park. That is an area we would enjoy returning to.
We had no issues crossing the border, but had looked up the taboo items online and purged them, and have no pets. Also, we allowed plenty of time so weren't stressed. Looking nervous could raise suspicion and prompt a deeper search.