In my opinion, this DLC map is the most underestimated in the community. Yes, it looks a lot like the base game "Layton Lake" map, but if like me you are from North America, these maps will be attracting to you because they look a lot like home. New England Mountains is like a Layton Lake upgrade in many aspects, so if you had fun with Layton Lake, covered most of the map and have visited each key locations but want more, this DLC will offer you what you're looking for.
Like all COTW maps it's very well made with some beautiful spots. Granted, it's a bit harder to find most of them as they will often be hidden within the forest. But like in real life over here in eastern Canada ( which has very similar environment and wild animals ), walking through a forest and suddenly discovering a cool spot, like a lake and its surroundings, is part of the thrill.
Still, one argument I'd have against this map would be that, like I said, landscape-speaking, it could've been eastern Canada. This would've allowed the developers to add extra animals that we have that New England doesn't, like cougars, wolves, hares, etc... Because we have almost all the animals found in this DLC over here, and then some.