Is this a good route in New England?

As mentioned, you may be a bit early for peak foliage... It really is like a curtain pulling down over New England, starts up near northern VT about late September, ends along the coast about a week after Columbus Day. Look for foliage websites for any of the New England states ("Yankee" magazine has a good one...) - may give you some time ideas from previous years. How are you arriving from TN (I presume based on your listing...)? If you have 5 weeks up here (not for the entire trip?) you have plenty of time to see some sites. You might want to re-think where you start/end your trip to catch some fall colors. Starting up in northern VT around Lake Champlain is nice - things to do include Ben and Jerry's Icecream, Vermont Country Store , Cabot Cheese, etc. Nice campgrounds around Burlington VT include city-run North Beach, and a couple just north in Grand Isle and vicinity. Move into northern NH, see some moose , visit Franconia Notch State Park, ride the tram up Cannon Mtn., walk thru The Flume. Drive across the Kancamagus Hiway from Lincoln. Poke around Lake Winnepesaukee - ride the excursion boat the Mt. Washington. Consider Ellacoya SP right on the lake (no pets, tho..., FHU only...). Head to North Conway area - consider a ride UP Mt Washington by the Cog Railway from Crawford Notch. Danforth Bay gets high ratings. Take either Rte 2 or 302 across Maine. Make SURE you get to Acadia National Park. Colors are still good there after they are fading in the mountains of VT and NH. Enjoy your way down the coast thru Rockland, Rockport, Camden. Visit LLBean in Freeport. NH has a short coastline, but another FHU SP at Hampton Beach, or cross into MA and visit Salisbury State Reservation. Salem, MA, on the "North Shore" above Boston, famous for colonial-era witch trials, is a neat place to visit in the weeks proceeding Halloween! Visit Boston - you likely have that on your list already. Don't by-pass CT too fast - a couple really nice things to see are the sub base in Groton and Mystic Seaport. Also Gilettes Castle. I'd avoid taking I-95 in or out of New England thru NYC - we usually use I-84/287 over the Tappan Zee Bridge. Hope this helps. Think I covered all the destinations you were looking for! PM me if you need/want more! ST

What time in September? You may be early for the leaves, even up north. Lots of rain and heat this year which sometimes delays the foliage colors. More will depend on how fast it starts to cool off towards the fall but so far the indicators are for a long, hot summer. Kids go back to school around Labor Day so during most of September it's not overly busy at campgrounds. Things book up quick, though, when the leaves start to turn. Have been on most of the roads you are taking with no issue, but also note the "coastal" route is a bit of a misnomer.

To do what you indicate you want to do, your route is fine. As mentioned, the traffic issues are more apt to occur on the Interstates and toll roads. The travel on route 1 in ME is what makes it a charming ride, not a fast one.

Enjoy, and travel safe.

Be advised that driving the coastal highway is like driving through a town that never ends. There may not be many people in Maine but it seems every one of them lives along the coast.

Loggenrock,
My plan was to try to get to recommended RV parks near areas of interest for 1st timers in New England using routes good for motorhomes. Then use the toad to see the sights. Of course, we want to see the fall leaves as well.

I welcome any routes you might suggest.

yes but watch out for holiday weekends and north bound traffic fri/sat and southbound sun/mon. Otherwise these routes are lightly traveled compared to big city ne areas.

Those roads are fine... It looks like you are going to VT and then coming back to the Rte 95 corridor - is that your plan? I might suggest a different loop otherwise... ST