I was there a few years ago in the last week of September. The leaves had just started their show.
There are a lot of little coastal towns that cater to guests and tourist that are a lot of fun. You can pick up a map of the hot spots just about everywhere.
We drove along the shore from York Harbor to Cape Porpoise and enjoyed watching the surf roll in, lobstah rolls, light houses, labstah rolls, cool little fishing towns with great shops, and labstah rolls.

Sig Experience Center

https://www.sigsauer.com/blog/...ter-in-new-hampshire

Camden midweek after Labor Day

The city of Bath is nice. Near Brunswick, Rt 24 leads to Bailey’s Island and Harpswell. Rt 24 is narrow and winding with many coves and inlets.