If it were me I would take the train between the cities and add any extra days you have to NYC. And yes, I think 5 days is too much for D.C., again add a few days to NYC.

Another option would be to drive between Boston and NYC and stop off in Newport RI and Mystic, CT. for a couple days.

I should have said - I've been to NY quite a bit so 5 nights is probably the maximum I'd want to stop there. My boyfriend hasn't been so I'm pretty much doing him a favour by going for that long!

I'll check out Newport and Mystic, thanks!

If you have a free night after Boston try to drop by Providence it is a great, fun smaller city that is a generic New England coastal city. I am not sure if Amtrak goes to Providence but you should rent a car if it doesn't. Five nights in DC is the maximum but that will give you time to see everything and have time to walk around freely. Try to stay in Philly and just do a hop on hop off bus if you have never been there before or even if you have only been there once. Sounds like a fun trip and you should be happy that you have so much time to do it.

Newport would be a nice place to stay between Boston and NYC but it would be more convenient with a car rental, though you could take the train to Providence and a bus to Newport.

I'd probably take Amtrak to Providence, stay there one night and continue on to NY.

If you do want Newport, you could also rent a car in Providence and return it the next day.

Philly.

While 4 nights is probably enough for DC itself, you could rent a car for one day and do a day trip to Charlottesville or some of the nearby Civil War towns. Virginia toward Charlottesvilleis beautiful country.

IMHO if you have never been to DC 5 days is NOT too much - esp if yuo intend to go to Arlington and Mount Vernon - most of a day all to itself.

As for Newport - I'm not sure which of the "cottages" are open and at what hours. If they're open - definitely fascinating.

I agree with nytraveler...5 nights in DC is definitely not too much...Smithsonian museums; monuments; Arlington & the changing of the guard at the Tomb of the Unknown Soldier; Embassy Row; National Cathedral; Holocaust Museum; Supreme Court; Tour Congress buildings; Georgetown and Dupont Circle; etc.

Did someone say 5 nights is too much…really?

I would keep your current plan with one possible thought.

While a week in DC is not too much, you can still EASILY do a day trip to Baltimore from DC on a weekday via a commuter train (the Camden line). The commuter trains do not run on weekends.

Take a commuter train from DC's Union Station ($7 each way per person). It's just over one hour each way. The train leaves from Union Station and ends near Baltimore's Inner Harbor. Buy your tickets from a MARC (or AMTRAK) kiosk. Be aware that the last train back to DC leaves Baltimore at 6:15 Pm.

http://mta.maryland.gov/sites/default/files/Camden_Aug12_gridonly.pdf

http://mta.maryland.gov/marc-fares