I think WN will reduce MHT and PVD service to PHL and pile on a few flights from BOS.... US looks they are already reducing some BOS-PHL and BOS-CLT to RJ service!
If that is really the case, why would I take a US RJ, pay for water, when I can take a WN 737. This is already the case in MHT and PVD when people need to make a decision. So I would guess:
BOS-PHL
BOS-Florida
BOS-MDW
BOS-PHX or LAS (They're going to stick it to US)