I concur with Jacqui about ground transport, localy in the states. Keep your eye out though thatmay change with the opening local competition with he likes of Ryan Air & others soon to possibility being let into the market.
Check out the trains. AMTRAK handles train transport from & through Portland, DOver-Portsmouth, Boston, Philly, Baltimore & DC. While you're in the North east I can help with your transport needs from Boston & Portsmouth & Back to Boston. We are a 1 car family but I'm retired & we can work around my wife's work schedule. Let us all know how your plans shape & we'll work around you. PM me with any questions, concerns, cares or wants. Good luck.

Chas, I never saw your world tour thread, I'll respond there.

Barry