Before the war, the National Park HQ was a large house used as the administration offices for Acadia National Park. By 2287, it had become a hideout for numerous super mutants, possibly former members of the group that inhabits the Vim! Pop factory.
The site consists of a two-story house, parking lot, and a large V-shaped barn. There is a steamer trunk in the wing of the barn closest to the house. The house itself contains a safe behind the front counter and numerous meat bags, but little else of note. Entering the barn will trigger the arrival of a super mutant suicider, a mutant hound, and another super mutant.
Several hundred yards west of the National Park HQ there are three ruined houses inhabited by feral ghouls. One of those houses is equipped with a mattress and a cooking station. The house with the mattress in it also has a safe under the trashcan in the kitchen.