I hiked from Elm East to FM 428 on the biking/hiking trail and took the equestrian/hiking trail back to my car. The TPWD map gives a distance of 4.5 miles between these two points. I give a difficulty score of "2" as an average of the two trails: a "1" for the biking/hiking trail and a "3" for the horse/hiking trail.
The biking/hiking trail is a usually dirt road sometimes paved with gravel and, once in a while, concrete. The northernmost mile is forested, but the rest runs alongside pastureland at the edge of the woods around the river. This might have been an unbearably sunny hike in August, but in January it was a great time to enjoy lots of plant and animal life. Coming this way, I saw a great variety of birds.
The equestrian/hiking trail is tougher going. The horse poop wasn't such a problem (looking where you step, it turns out, is the easy part). However, the soft, sandy ground certainly made walking more of an exercise. There were LOTS of muddy sections that sometimes sent me off the trail in search of a detour. This might have been impossible in a summer's dense foliage. This trail goes through much more forest and is much hillier than the biking trail. In a number of ways, it was the more pleasant of the two trails. I saw a good bit more wildlife--even a deer at one point. But next time I'll choose shoes better suited for wading in mud. And I'll be better prepared for the physical demands--this trip left me pretty sore in the hips and legs!
I only saw two people the whole time: one elderly biker and a TPWD patrolman in a pickup truck.