I use to travel to New England for work a lot a few years ago. The coast of Maine is awesome going from Ogunquit all the way up to Boothbay Harbor. Gazebo Inn in Ogunquit is nice and if you want to be budget friendly Meadowmere Resort is nice and walking distance from anything. In BoothBay Harbor The Greenleaf Inn, Topside Inn and Five Gables Inn are all nice B&B’s.
New Hampshire is kinda of a sh**hole but I’ve stayed at Mountain View Grand Resort and that would be a good drive up during the fall colors. Its funny people from Maine and Vermont would all tell me that New Hampshire is like the forgotten step child of New England.
Stowe in Vermont is an amazing place in my opinion. Lots of good lodging options and beautiful scenery. The Lodge at Spruce Peak and Smugglers Notch are great resorts but if you are looking for B&B Stone Hill Inn or Edson Hill if I remember are good.