It is not the biggest, you are thinking of Sugarloaf. Don't think any buses head there though I may be wrong.
Saddleback is a good mountain, but if you are looking for a resort, Sugarloaf is the place to go. Walk right out of the condo onto a lift, plus bars and stores right on site. One of the biggest verticals in the east with above treeline boarding at the summit. 1000+ acres of terrain with tons of glades and trails. Huge park too, though I don't ride park.
Might be able to take a quick flight into Portland and rent a car or take a bus from there.