Can't say anything about Minuteman since I really know nothing of it.
Normandy Farms is a FHU with a lot of auxiliary amenities and charges accordingly.
Wompatuck is a state park with about half the sites offering electric hookups.
Both campgrounds are close to mass transit but Normandy Farms is a bit further away. I would check to see what the cost difference and transport schedules are to help make a decision as to where to stay.
Were I planning to tour a pedestrian friendly city with lots to keep me out of the campground not sure I'd be focused on swimming pools, arts and crafts facilities, or movies back at the campground since prolly wouldn't get the benefits of it. For my way of thinking NF and possibly Minuteman, would be great if I was planning an extended visit in the area and could break up time visiting Boston.
I've made the "mistake" of playing tour guide with friends visiting NYC. We come back home foot tired, "fight" for shower usage then collapse in the nearest available cushy chair. Sometimes I can't even muster the energy to heat up a meal and with my last remaining strength feebly dial the phone for takeout;).
This is the mindset urban visitors should concentrate on so my vote given the stated time frame (a few days) and objective of the OP (touring) would go to the state park. I'd spend the money saved on an especially nice meal or spa treatments in Boston/Philly/SF....you get the picture, LOL.