5 or 7 days enough?
Looks impossible.
In my experience, you need at least 9 days for them.
Washington DC > 2-3 days
费城 > 0.5 - 1 day
NY > 3-4 days
Boston > 2-3 days
The above schedule is very tight. I believe no one can make it in the consequently timeline. Too tired, if you visit those museums in DC, NY and Boston. But I guess you can't miss them, otherwise, you lose the spirit of the trip.
BTW, if you want to visit whitehouse, you'd better to make reservation 2 months ago. For having a look at the inside of the capital hall, you'd better pick up the ticket very early morning since they are gone very fast on weekend.