Some Tips to Get You Started
Welcome aboard the RoadTrip America Forums!
Well fortunately may is about as low as a low season gets, so wherever rates or admission prices fluctuate through the year, they'll be at their low point. It also will be getting warm enough to camp out some nights, but be forewarned that may is referred to as 'mud season' in some parts of northern New England. I would recommend that you start looking for accommodations beforehand and always ask if there is a discount for booking multiple nights. Staying in a different place each day and taking rack rate are two of the most expensive 'penalties' in travel, and New England is compact enough that you can see much of it from a few well chosen bases.
The coast of New England is certainly photogenic with some of the best sights in Mystic CT, Newport RI, Cape Ann MA, and Down East ME. There is also a thriving art scene, but it is spread out over a number of small towns and intimate galleries, so finding what you want will take some leg work, but once you've found one good gallery they should be able to recommend some others, and those will know of still others, etc. For some more general hints on what to see and do in New England, check out the discussions linked to here.
AZBuck