Well, living here in Vermont I can say that we have the best fall foliage :-)

Lodging is at a premium (hotels/BB) this time of year. I'm leaving Sat (Oct 10) for a 3 day tour and staying at state campgrounds and they have plenty of openings (just checked). As for traffic, the best color and sites & sights are along the back roads that most visitors in cars do not take. They tend to drive on Rt 100 and other main state roads. The big question is always when will the leaves change. The ACA route takes you north to the Canadian border (and into Canada) and up there the foliage has changed a couple of weeks ago. Along the NH border, foliage is changing big time now, as it is along with Lake Champlain area. The ACA route is very nice and it really exposes you to all the different areas of Vermont. Another option would be to look at the Lake Champlain bikeway (lakechamplainbikeways.org) site for their route around the lake.

Any other questions, be happy to answer for you,
Brian