I'm working on a new route that hooks up with the Gaspe. To be completely honest, there are certain large sections of the Maine route that trouble me. In my experience, the situation with land ownership has been very fluid over much of the route that's not on public roads. One season, a section will be perfectly legal. The next, ownership will have changed, and it will be illegal. Certain of the timber companies have been quite liberal about allowing motorcycle access. Several of them are absolutely not, and private corporations and individuals are purchasing large tracts of land with the intention of prohibiting almost all motorized access. Most of the Allagash/North Maine Woods is off-limits to legal motorcycle travel, as is Katadhin.
Try this: take a map and look at the border of Quebec, New Hampshire, and Maine. Starting at Canaan, VT, Route 253 heads north towards Hereford, QC. Following tightly along the western border of NH and Maine, there appears to be a fairly good collection of mostly gravel roads that can be connected up as far as Matane, QC.
I did quite a lot of mapping for this route last year. Unfortunately, it was lost in a computer crash. I intend to re-start the project when the weather gets better.
It appears that this route may have more promise. It goes through some very wild country, but does not appear at this point to have the access restrictions that plague Maine. It connects into the TCAT, and offers access into many rides across Canada.
The current NNEAT route is attached as a GPX file, which can be imported into Google Maps or Google Earth.