The Trinity Forest Trail is one of the most beautiful we have in the entire city. It's fine for running, but it feels much safer on a bike. It's flat, much like the rest of Dallas, so don't plan on getting a huge quad workout, but do take a ride to experience the overwhelming beauty that is the Great Trinity Forest. There's no loop, but going back and forth allows you to take in different perspectives of the landscape. Enter at the small entrance near 4608 TX-12 Loop (west of the Audubon) to get as much mileage as possible, connecting to the AT&T Trail, which will show off Dallas' best boondoggles (the golf course and horse park).