Spring break ideas: two 8yo kids, 1 adult, no car?

DC, Philly, Boston- all good choices!! 

there is a train station near point pleasant for a day trip...i'm not sure of their hours though

we had fun in Philly! No car needed. Great hotel deals on Hotwire.

philly has the Zoo, Franklin Museum, you can take Septa to Camden Aquarium, Historical sites, Parks

Lots to do in NYC.  You can take the train in and back each day if you want to stay closer to home.

I think DC has the best combination of museums and public transit if you are leaving town.

Boston is also a fun destination for kids - reachable by bus or Amtrak and it's very walkable. There's the Freedom Trail, the Aquarium, the Constitution....Philly, Washington or Boston are all great cities to visit with kids, and all of them have interesting historical places to visit that will be talked about in history classes in elementary school.

When I took my elementary-age twins (and older daughter) on a spring break vacation on my own, I took them to Rocking Horse ranch, which they love.  I believe they run a free shuttle service to the nearest train station (although we drove), and are all inclusive, so no reason to leave.

I think I wrote up a long debrief on the place on MOL, and can find it if it isn't easily searchable. Many activities, and just a lovely family-run resort, well renovated.