Thanks for the query puzzled54… here's the dilemma deciding when to visit New England for the fall colors… Firstly, the onset of the change (and it is magnificent) is usually about the middle of September, but that can be dependent on the weather… if it's been a dry summer, the colors may begin a couple of weeks early and if it's been wet maybe a week or two later.
Regardless, anytime between third week of September up through middle of October is great… but down side of that is that everyone knows it and sometimes the crowds can be uncomfortable. But, often, the commercial tours in busses adhere to pretty set routes. The most popular routes are leaving Boston through southern New Hampshire, up the Connecticut River (boundary between Vermont and New Hampshire), maybe making a swing east across northern end of New Hampshire and returning to Boston. Most of the inbound "Peepers" (so called by locals) arrive in Boston by air or bus.
If I were to go I'd still arrive in Boston and plan on a couple of days in Boston itself. In the middle of the city (easily accessible) is
Faneuil Hall where the 'Freedom Trail' begins or ends. The hall, among other things, has a long interior that contains food stalls from all over the world… kinda amazing to experience.
The Freedom Trail is a walking tour of historical sites led by red bricks inset into the sidewalk as a guide… Old North Church ("One if by land, two if by sea"). Paul Revere home and much more.
So, after Boston, personally, I'd go to Portland Maine… about 80 miles or so on a good Interstate Highway (Highway 1 north to Interstate 95) about 1.5 to 2.0 hours. Several side trips available to see the plethora of coastal lighthouses, especially the Portland Head Light shouldn't be missed.
15 miles or so north out of Portland (North on Interstate 295) is Freeport, Maine, home of L.L. Bean, one of the world's largest outdoor and sporting goods store… it'll take a full day to tour. (Just outside the front entrance which is designed to look like a Maine north woods is a Ben and Jerry's ice cream stand… Ben and Jerry's is the premier ice cream maker in all the world according to most of us here. Have a Cherry Garcia cone!
So…Ok… leaving either Portland or Freeport, one would make their way northwest (check the map) up the Androscoggin River Valley to White Mountain National Forest (especially Franconia Notch). This takes you out of Maine into the northern sections of New Hampshire and Vermont. The highest peak east of the Mississippi River is there… Mt. Washington, New Hampshire where the highest winds in America were recorded years ago… pine and maple forests full of color.
From there one would return to southern New Hampshire/Vermont and on back to Boston.
Here's a link to a good map:
https://maps.google.com/maps?client=safari&oe=UTF-8&q=Map+of+Maine&ie=UTF-8&hq=&hnear=0x4cb01dde1d538ad5:0xd679cc6f6720a8d0,Maine&gl=us&ei=PnTYUrDtEdfBoATxvoCICQ&ved=0CCYQ8gEwAA (apologies for the long URL.
Here's a good site for exploring before hand:
http://www.discovernewengland.org/driving-tours/fall-foliage-one-week-drive/
And another:
http://discover.mapquest.com/collections/driving-discovery-vermont-new-hampshire-maine-749
Lots to do and lots to see…I'm sure I've overloaded you, but if you have specific questions, please post them...