Part of the Monmouth County Park System, Clayton Park is an easy 25-minute shot from Trenton (off I-195 Exit 11). It’s absolutely lovely, featuring 8 miles of trails through a mixed habitat of mature hardwood forest, wetlands, and fields. The topography is rolling hills…there’s no more than a hundred feet or so of elevation gain at any one climb, but you can string together a few of those climbs to improve the aerobic value. More popular as a MTB trail than as a hiking trail, but both activites are lovely. (Driving time is just about 30 minutes, Rated for Beginner to Intermediate cyclists or hikers depending on where you go).