Check for ticks after! Very nice trail through woods. There are some moderate hills. There are a few trails in the San Felasco Park. Off of 53rd (Millhopper Road) Avenue there is a trail north and south of 53rd. There is another access for off-road biking and horseback of 441 (North). Both are excellent trails.
There are over 50 miles of single track trails here at San Felasco Hammock and though they are used mainly for horseback riding & mt biking, they are great for hiking. Just yield to bikers. Weekdays are best to avoid mt bike traffic. I believe the trails here are some of the finest in the State. And if you're a mt biker, you will love this place.
One of the best trails around for road biking. Watch out for heavy pedestrian/rollerblade/stroller traffic the first couple of miles, but after that the traffic fades away and you get to experience many different ecosystems with little traffic (except the occasional cross street) to worry about. Hit up the trail early in the morning and you will likely see turkeys and deer, and maybe even a wild boar. Just don't get too relaxed, as these critters are unpredictable (I came up on a guy who had somersaulted his bike over a wild boar one time).
Really, the Gainesville-Hawthorne trail is one of the true gems in this area, a very scenic ride, and a great way to get some shaded exercise in the brutal Florida summer.