Boston

Two places seem to get the most mention when this comes up

Minuteman

Normandy Farms

Both are close to commuter rail lines that go into Boston.

The historic walking tour, the Freedom Trail (known locally as "the stupid red line") visits several historical sites around the city. You really want decent weather for this and would be tiring for kids.

The Prudential tower has an observation deck that's great on a good day.

And then there's the Duck Boat Tour in WWII amphib vehicle that rolls through parts of downtown Boston and ends up in the Charles River.

Lots to do, just don't even think about taking the HR into the city.

You are in luck because there have been a few campgrounds recommended along with bus tours. Just search this Forum for Boston in the RV Parks section then search the results for `tours'.

We lived out there for 4 years and Normandy Farms was our 'near home' campground for 2-4 weekend a year. We're headed back there next summer for a week and will spend all of it there. We miss having it nearby.

Boston/Cape Cod KOA in Middleboro MA. Not to far from Boston. MBTA commuter train is close by and travels several times a day.

I like the place and stay there every year. Lots of things to do in that area as well, like Plymouth Plantation.