Every New Englander will boast, with some degree of accuracy, that it is the arrival of the sharp autumn frosts that bring out the colors with their greatest vividness; and that a rainy summer helps add intensity, too. Other sections of the world boast autumn colors to some degree; but only Khamchatka Peninsula in the Russian Far east posseses the hundreds of miles of hardwoods that the eastern US has in abundance. Even there (and I have been close) the colors are not as vivid. Besides, half the fun of Vermont is the Vermonters themselves. Perfect hosts and proud of the spine of independence in their state (Bernie Sanders, former mayor of Burlington, is the only non Republicrat in Congress.), they are hard workers who draw maple syrup in spring, hay and milk all summer, harvest and prune in the fall. In the winter, which lasts seven months in some parts of this seemingly sub-alpine state, Vermonters can get a bit crotchety, like a bear woken prematurely from hibernation.
I have ridden over 28,000 miles on cycling tours throughout the Northern Hemipshere, and only Vermont has the honor of forcing me to walk at least once whenever I visit the state. In the south, dastardly route 9 west of Brattleboro just thows hills at you as you climb Hogback Mtn. In the middle of the state, Lincoln notch brought me to my knees in the dirt...its not paved (yet). Worst of all, in this northern portion is Smugglers notch, north of Stowe and fiercely steep amidst the siwtchbacks around boulders.
By the way, on a calm morning you may be lucky enough to smell the foliage, not just see it. For the leaves, still waxy and supple despite being guillotined by a thin layer of cork, have a most pleasant..well, leafy odor! The photo below shows foliage still on the tree, close up; with the early morning sun shining thru. If you haven't seen or cycled thru the foliage of New England, do it soon. The forests, instead of being cool, gloomy and shady with the dense canopy of summer, are now bright and cheerful with a riot of reds, yellows, and gold.
The foliage generally is at its peak in northern New England the last week of september; peaking in the south if mid October, but this varies. State tourist authorities can clue you in to areas which are at their peak.