I stayed here for the first time in August last year, but returned in October this year to enjoy the autumn colors. This is a lovely state park on a large lake, offering drive-in sites with and without water/electric hookups plus a number of primitive boat-in sites around the lake. In 2019 the bathhouse was renovated, delaying the season opening, but it was worth the weight. Bathrooms are clean and bright, offering hot showers ($) and laundry.
Site fill up on weekends, especially prime lakefront sites. You can choose something more open and grassy or a wooded site. There's a swimming area and boat rentals. The office has limited hours. If you arrive after 5 or 6 (depending on the day/month), you'll need to check in in the morning and won't be able to buy firewood on site.
Off site, it's a short drive to Grafton Notch State Park (ME) for hiking and waterfalls, a little farther to Bethel, ME for canoeing, biking, and other outdoor activities. The Umbabog National Wildlife Refuge also offers hiking and boating opportunities with moose, loons, eagles, and beavers, to name a few.
It was bitterly cold overnight (24-27 degrees), so I was grateful for my trailer, but it made for some beautiful, if foggy, mornings and brilliantly clear skies for stargazing. If a tent or trailer isn't your chohice, there are cabins available, too.