Trout Creek Park is just one of a network of parks in northeast Hillsborough County, known as the Wilderness Parks. If you haven’t been there, I highly recommend you check it out. The entrance to the park is just east of where I-75 crosses over Fletcher Road.
As far as running, there are only a couple of miles of trails in Trout Creek Park, BUT most runners park there and then run up on what is known as ‘the berm,’ run just about a quarter mile, north, and then take a trail down from the berm into amazing wooded single-track trails. At that point, you’re in Flatwoods Park. Flatwoods can also be accessed – and usually is accessed – from Bruce B. Downs on the west or from Morris Bridge Road on the east.
I prefer to park at Trout Creek and access the trails from there because the wooded trails are very close to the parking lot. A trail, known as the Main trail, connects the trails, and together comprise a roughly 14-mile off road loop. You can make many much smaller routes or add other shorter trails to get more miles.
For people who want to enjoy the trails but aren’t trail runners, I recommend this: Take the trail up to the berm, then dip down onto the Main from there, and take that trail to the asphalt7-mile loop in Flatwoods, do however many miles you want to do on that loop, and then take the off road trail back. That’s a total of about 11 miles if you do the whole loop. For non-trail runners, just hike the off road part of that, at least parts with roots. Sections like below aren’t much different from asphalt trails because there are long sections without roots.