The New England Mountain Bike Association has published an article that explains where E-bikes are permitted to be ridden in New England. This information is important because manufacturers and retailers do not always properly represent where the bikes they sell can be legally operated. You can read the story in its entirety by clicking here.
The biggest takeaway from the article (that mostly addresses off-pavement riding) is that in New England, E-bikes ridden off pavement are welcome on off-road trails currently designated for motorized vehicle use. They are not permitted on multi-use trails open to hikers and mountain bikers.