You are not supposed to run in the Arboretum. Trails are designed for hiking only.
This pinched-loop trail is easy to get to from the parking area or visitor center of the Houston Arboretum - just look for the yellow signs. The trail is a wide singletrack that is easy to pass others on and could accommodate strollers. There are a few boardwalks over wet areas and other parts of the trail are made of a wood chip fill. Half the loop follows the Arboretum's entrance road, while the other half is a little farther into the woods. If you want to make the Outer Loop
an actual full loop, you'll use part of this trail.