The Basics In Maine, they've got the ocean. In New Hampshire, they've got high mountains covered in pine trees. Pine trees do not change color in the winter time. It took me awhile to figure this out, but I'm pretty sure that it is true. In Vermont, they've got lower mountains covered in deciduous trees.
Deciduous trees change color in the winter time.
Dead Trees Start with the Michelin Green Guide to New England . This book has excellent driving tours with all the important sights marked with stars. They have a particularly nice tour for the White Mountains of New Hampshire. Finally, pick up the state tourist board maps as you cross borders. These are useful for pinpointing covered bridges and such.