Ok so maybe I'm biased because I've been here so many times, but this park is a little slice of heaven. Because the weather on the lake is extremely variable, you never really know what your experience will be like until just before you go. If it's hot, no problem, you have an ice cold lake a few steps away! Mosquitoes can be bad, so bring the spray.
Access to Lake Superior can't be beat - there is plenty of room to spread out and avoid a crowd, if you're so inclined.
There are cabins to rent, but they typically fill up with reservations pretty quickly. There are a few campsites that are more private, but in many cases you might have neighbors close by. There's a fantastic ice cream shop on the far end of the park - you can either hike nicely groomed trails to get to it, or take a car or bike on the paved road. There's also a good sized playground, large field, picnic shelters, and a horseshoe pit.
Great, well maintained campground! The sites are close together but most spots are tucked neatly among the trees so it still feels like you're in the woods. Other campers were very friendly and respectful; we were there for the Fourth of July. Bathrooms are modern and clean.
We stayed in a "rustic" yurt (#47) - which had no water or electricity, but there was a spigot and outlet right across the road at the bathroom. The yurt itself was well appointed, with things like bedding, a trash can, and even a privacy screen. We brought sleeping bags to use, and ended up using them anyway.
$90/night might seem expensive for a campground, but considering this is so close to Ogunquit and the beaches, it's worth every penny for those who aren't looking to tent (or can't) and don't have a trailer.
Pay showers.
There are some wonderful sites in this campground, but not all of them have privacy. We really lucked out with getting one of a few sites left on Memorial Day weekend - after walking the campground, I think we would have chosen the same one again! #18 is right next to a ravine, so it was wooded on one side, and the two adjacent camps were visible but not on top of us. The trees are primarily pine, which made for pretty comfy tenting. Was a short walk to the facilities, but not close enough for the foot traffic to be annoying.
I loved that there were trails to hike from right in the park; you could do a short one, or a slightly longer loop (2.5 hours depending on your pace) with some inclines and boulders to scramble up and over. We were on foot, but it would be challenging for mt. bikers in some spots.