Ann Lake, Sand Dunes State Forest is a 2 mile loop trail located near Big Lake, MN. The trail is rated as moderate and primarily used for hiking.
Had a lot of fun at Sand Dunes when I went last summer with a friend. Parked on one side of the forest and started hiking around, conveniently passing Ann Lake along the way which is a nice, small, and relatively quiet little beach to swim in. After swimming we continued our hike with an adventure to find the car. Luckily we got right to it, but the maps are a little hard to read, so I would recommend taking a worthy note of where you parked before you venture out.
Overall a very fun trip, I don't think we ran into anyone else along the hiking trails until we got closer to Ann Lake because the trail is large and there are multiple routes to take through it.