Dover would not be a good fit IMO they may be a "city" but it's very much a small town in terms of night life, downtown area, and meeting new people. Not a ton of walking trails removed from the traffic, most of them are far drives from here.

Idk about Concord area but just remember this is a small state where most people grow up in one town and never leave and have their established friend groups. It's hard to meet people here.