There are two designated swimming areas at Moraine State Park; between them, the southern beach (“Pleasant Valley”) is far superior, in my opinion. Not only is the permitted swimming area larger at Pleasant Valley, but it tends to be less crowded (!). Although the other beach (“Lakeview”) has more extensive amenities, this is the only edge it has. The view of the lake is better at Pleasant Valley as well; it feels more spacious and attractive than the view at the Lakeview beach does.
Of the various trails at Moraine, two deserve special mention. One, Glacier Ridge, is accessible from various parking areas scattered among the northern section of the park. I suggest parking at the de facto “Glacier Ridge Trailhead,” which is the first parking lot after the bicycle rental building if you’re heading east on North Shore Drive. If need be, you can also park at the bicycle rental building, but that necessitates walking on a portion of the bike trail…and while enjoyable, the bike trail is far too controlled and predictable to be considered preferable to Glacier Ridge. The trail is rather lengthy (14 miles), and although there is a shelter, most hikers will want to simply turn around after a few miles. There aren’t any real sights of note on the part of the trail I’m familiar with; rather, the trail is simply enjoyable for what it is, a meandering path through the woods, with a few cool bridges and views of the lake to offer diversions. Also note that Glacier Ridge is also known as the “North Country Trail” on the map.
The other trail of note is the Sunken Garden Trail, which can be accessed via the parking lot for the Pleasant Valley beach (actually, there’s an earlier parking lot that you can use as well, but if you’re planning on swimming as well, it’s probably best to park closer to the beach and then walk to the trailhead, as opposed to vice-versa). The name of the trail is particularly accurate in this instance; there is an extended section that runs alongside the lake, featuring flowers and other richly colored vegetation that dwarf pedestrians. There are a few cutoffs that lead down to the lake, providing some excellent views of the area. Two ways of hiking the trail exist: a short loop and a longer loop. Because the shorter version of the trail can be walked in as little as forty minutes, this is a great trail to hike if you’re pressed for time.
Although there are trails at McConnell’s Mill, to be honest, none are all that impressive. The Alpha Pass Trail (which heads north from the Mill proper) is probably the best, and there are definitely some cool views of Slippery Rock Creek from the various trails, but to be honest, the best reason to visit is to simply see the Mill. It certainly won’t take you very long to explore the mill, but it’s definitely worth seeing a watermill in “action.” Because Moraine State Park is so close, you don’t have to feel guilty about driving all the way just to see a historic site; you can take a look around McConnell’s Mill for a few minutes, perhaps marvel (?) at the covered bridge, and then drive a few minutes east to Moraine, where better trails and recreational activities await.
Directions (to Moraine State Park): From I-79, there are two exits that will lead to the park (Exit 99 and Exit 96). To access the northern section of the park, take Exit 99; there’ll be signs indicating which road to take. Exit 99 also leads to the southern section of the park, but you’ll have to stay on Rt. 422 for a bit. If you’re coming from the south (i.e., Pittsburgh), I suggest taking Exit 96; make a right onto Rt. 488, and then take a left onto Pleasant Valley Road (don’t worry, there are signs for the park at the turn). This road will lead you directly into the southern section of the park, where Pleasant Valley beach is located.
Directions (To McConnell’s Mill): If you’ve already visited Moraine State Park, all you have to do is get on Rt. 422 west; McConnell’s Mill Road will be on your left. This is the road that leads into the “main” section of the park. If you decide to visit McConnell’s Mill first, take Exit 99 off of I-79 and turn left on Rt. 422; again, the turn will be on your left.