There is a developing series of trails in the area of the original Trinity River watercourse (now mainly dry). One section is the 2.5-mile Trinity Strand Trail, which runs from Oak Lawn Ave., just south of I-35, past the Hilton Anatole, paralleling Irving Blvd. It is paved and pretty urban, but a good off-road option.
The second option in the area is the Trinity Skyline Trail, which offers 4.6 miles of paved path, plus several more miles of dirt path, in the old riverbed and along the levee (Trinity Levee Trail). It’s a pretty unique experience — a huge, open, below grade area, steps from and with great views of Dallas’ skyscrapers. The Trinity Skyline Trail is the paved path, while the other trails in the riverbed are a gravel/stone surface that can be a bit challenging for running. One can put together a long run here: From Moore Park at the eastern end, it’s 2.6 miles to the W. Commerce Bridge, 3.3 miles to the Ronald Kirk Pedestrian Bridge, and 7 miles to Inwood Rd. The trail is not well way-marked.
Trammell Crow Park is a good access point and parking area on the trail. Other good access points are from Main St./Dealey Plaza (JFK Assassination Site), Trinity Overlook Park off the Commerce St. bridge, and the Ronald Kirk Pedestrian Bridge. Note: this trail is very exposed–there is little shade. It can be windy, hot, muggy, or buggy, depending on the conditions.
There’s a plan to connect the Trinity Trail to the Katy Trail, which is also nearby. It’s part of a planned 8-mile trail, which will be a terrific addition to the downtown Dallas running scene. More info here.