Afton State Park's 1,620 acres make up one of the larger forest and prairie preserves in the Midwest, cut with winding paths and deep sandstone ravines. In this sense, the park has at least one thing in common with the Twin Cities: It's big enough to get lost in but easy to find your way out of. And clearly, it's not for the timid. Campsites are open all year and require that you hike in. All told, the trails stretch for more than 20 miles along the beautiful St. Croix River (a reasonable 30-minute drive from downtown St. Paul) with plenty of places to pause, like the summer beach. The park happens to lie in a migratory corridor, so bonus points for anyone who spies a turkey vulture or bald eagle.