This would be ok for Southern VT, but for green, gold and crimson in the Northeast Kingdom, peak is usually end of September, and by mid-October the leaves are mostly down. I like the views off rt 17 as you come over the Green Mountain Ridge and stare down either side - on the west there is a small mountain lake, and I have watched a moose family taking water at it's edge, and on the east there is the glacial cirque that has become Mad River Glen ski area with the peak of General Stark mountain being the highest point. The nearest town of any size is Waitsfield, a crusty old place with a few good restaurants, and three covered bridges - one over the Pine Brook, and two over the Mad River. Further south in nearby Warren, there is another covered bridge over the Mad River.

Anywhere along Rt 100 which parallels the Green Mountains would be a suitable, but I will caution you that your plan is very ambitious. You can spend weeks at just about any place in VT hiking and viewing - so I would focus on quality over quantity. In southern VT the view as you come into the town of Bennington from the west on rt 9 is pretty stunning when the trees are in peak, probably in the middle your time frame. Be prepared for tons of out of towners doing what you are doing, and try to plan your trip utilizing back roads as much as possible, and you will successfully avoid most of the hordes.