Rates in New England totally depend on where you are, when you are there, and what else is going on at that time. A hotel can be $90 a night, and then just a couple nights later be $55 a night .
I took a quick look at the Hampton Inn in Milford, CT. Only because a few years ago we stayed there for quite a few nights on and off while we were in house closing hell. On the night of Saturday July 17, rooms are as low as $55 a night. On Thursday the 15th, they are getting $88 for the same category of room.
Once you have the dates and about where you want to be each night, start searching in the area. If you happen to pick a hotel or motel that is putting up people for a local cat show or country fair, rates may be high. If you look at a place across the street that is not a recommended venue for those shows, rates may be quite low.
I know, it's not the xyz hotel is always the least expensive answer you were looking for, it's just that prices are all over the place in the summer.
Also watch out for places that require two nights on weekends in the summer, make sure there's nothing in the terms stating that's necessary.
If you have a tent, there are some nice campgrounds but they are probably already sold out.