I’m always impressed with the excellent work done by the state park system. There are so many wonderful areas to explore, hike, picnic, camp, and canoe that the possibilities are endless.
Camden Hills State Park
Lots of trails and Megunticook Mt has excellent views over Camden and Mt Battie auto road. Very busy place in the winter for X-country skiing.
Holbrook Island State Park:
Just across the bay from where I live, Holbrook offers some nice, but short trails on the mainland. I like to trail run there and snowshoeing is great. There is also Holbrook Island which requires a boat ride to get there.
There is just too much to even begin to list here. The highest mountain in Maine resides here as well as so many other excellent mountains. The AT terminus is on Baxter Peak so there is a lot of traffic in this park.