Oddly enough, there aren't too many walking trails throughout H.H.I. One of the few that I found on my adventure was Newhall Preserve Trail, which is a little hard to locate. A driveway on the side of the road leads to a small spot for a few cars and a trail. The Newhall Preserve was established in the '60s as the only wildlife preserve on the island. It would have been trampled by developers if it wasn't for lots of hard work and love by founder, Caroline Newhall.
When you first start the trail, it seems a little overgrown and barren, but if you keep going (bikes are allowed), there are multiple areas that you can reach, including a pond, boardwalk, three wood trails, and a fine flatwood trail.
It's a perfect way to spend an afternoon in quiet solitude, among herons, chorus frogs, and several different kinds of pines, maples, and oak trees.
Tip: Cars can't reach any of the trails, the pond, or the boardwalk. You'll have to walk or ride a bike to get past the information booth.