Started in Farmersville and did the 2 1/2 miles to the crushed stone to the northeast. Frankly even that 2 1/2 mile was a real problem for us. My wife and I are 65+ with health issues that make riding recumbent trikes necessary.
The first issue is with the bollards that are used at each intersection with the crossing streets and roads. While I understand the need for them, they really should be spaced differently. Put the middle bollard a little to one side. That way, cars and other motorized vehicles are still blocked, but we can still get thru. We had some of these that we had about an inch on either side of our wheels requiring us to virtually stop to get thru. At one road, it was just easier to hit the grass and go around, as I saw several bikers doing.
The other issue is the bridge at about the 2 mile mark. The bridge is significantly above the height of the road. There is no gradual incline to the bridge. It's a very short incline with a very severe bump at the top. We barely cleared our frames getting over it.
Finally, the other issue is just the condition of the trail. The concrete sections are in pretty good shape, the asphalt sections are not. Then there is the issue with all of the horse droppings.
Since there are so few trails for non motorized vehicles in this area, we thought we would try this trail out. Frankly, this is the worst trail we've dealt with so far.

Quiet and Serene and peaceful. however for biking very hilly. Maybe not so much for casual older Riders

I took a troop on a hike from Farmersville to Celeste on October 3. The section from Farmersville to Merit is, as mentioned in many reviews below, in excellent shape. From Merit to Celeste is vastly improved from work done over the summer of 2020. There are still large rocks in the gravel, and there are still areas that will probably pose a problem after a rain, but the underbrush has been cleared significantly and the road graded. One critique—the brush has been cut back so much that there is far less shade from Merit to Celeste than from Farmersville to Merit.

A really easy ride through nature, history, and amenities of Allen. Who knew? Allen Heritage Village. Hydrous (wake board training facility). Historic water station, railway, and bridges. Recreational facilities.

What a nice trail! Wide enough for bikes & walking/running. The little foot paths to the limestone quarry & stream are great! It’s a short walk but looks promising that it is continuing up by the SRT!

I ride this path a lot because it is in my neighborhood. Going south, the trail actually goes under Mckinney Ranch and continues all the way to Collin Mckinney Pkwy where it dead ends at the creek/dead end bridge. I like the scenery, creek, ponds and multiple tunnels you travel through.

Wasn’t impressed. Poorly marked at the beginning portion of the trail and through the golf course area. It appears the narrow paths through the golf course are the old golf cart paths and most are in badly need of repair and should be widen or upgraded completely. Trail connected to McKinney's Craig Ranch, but didn't go much more than a mile north of 121. So close to Frisco and Plano, I would have thought there would be better signage and connecting trails, disappointing.

Great improvement from Merrit. Very clean and well maintained. Very nice shade.

Nice wide trail, not too crowded and a good mixture of hills and flat. You can make it as long or short as you want.