The Fall foliage “peak weeks” tend to follow a pretty consistent pattern every year in New England:
1st week in October is when very northern NH/VT and Western ME areas are peak
2nd week in October is when northern and central NH/VT areas are peak
3rd week in October is when central and southern NH/VT areas are peak
4th week is October is when southern NH/VT and northern and western MA are peak
Although it follows this pattern, the exact timing is very temperamental and sensitive to weather conditions; all it takes is one cold night with temps dropping below 32F, or a night filled w/ heavy rain, to wipe out a bunch of trees. Due to this ephemeral nature, some years the prime colors are ever-elusive and not really prominent anywhere. Other years, it’s absolutely gorgeous everywhere.
The best source for local, updated information is from local people who are addicted to foliage — there are users who regularly post on here every year for the past decade (e.g., ctyanky is an expert). I think it’s a bunch of older folks who know each other.
Using that forum as a guide, I’ve often made Google Maps of the roads that people have recommended during the times I took trips to the area. Below are those maps:
Regardless of if those mapped roads are at peak or not, they are all scenic and I recommend checking them out. The Kancamagus highway is highly popular, but for a reason — it’s great!
I tend to like VT more than NH because it’s way more rural, no billboards are allowed, and there are tons of barns, silos, curvy roads, independent maple syrup sellers, etc. I think it’s most fun to just explore random roads and stop at a bunch of waterfalls. There are a bunch that I like: Moss Glen Falls (the one in Stowe, not Granville… two waterfalls have the same name), Sabbaday Falls, and Arethusa Falls are my favorites (off the top of my head, but if you click 2010 or 2011 Google Maps, you’ll notice that I sometimes provided my rating of select waterfalls.
Enjoy!