Your options will be pretty limited once you go over 40' in New England. There aren't a lot of campgrounds that will be able to accomodate that size. Make sure you plan for the stops you want to make and research for campgrounds that can handle it along the way. The other thing to consider is your height, particularly in New England where there are a number of bridges with low clearances. So, know the height of your rig before you take off. Typically, if a tractor trailer can go that route, so can you. Suggest you get a truckers GPS to plan your route to avoid those issues.
Tim