Most libraries have museum passes for all of these museums that are mentioned. You can get discounted or free access as long as you book it ahead of time.

You will also be near a few historical national parks and only a 4-6 hour (depending on traffic) ride to Acadia, our only National Park park. The National Seashore runs along the Cape and the seal tours are really fun, just keep an eye out for great whites. One went under a tour boat the week before we went out.

Ticks are an issue, so don't forget to prepare for that!