This park extension is on the West side of FM2288 directly across from the North Shore check-in station. There is no official trail but I followed the old dirt service road that parallels the North Concho River. Route out is three (3) miles which is the same route I took to return. Take a look at Google Earth for a better view but the old road basically goes West until you hit the park boundary by a farmstead which has donkeys.
I was on this route almost two weeks ago and wanted to see if I could find more wildlife if I hiked earlier so I arrived when the park opened and started walking. Definitely more birds were found - a great blue heron, ducks, Mississippi Kites, turkey vultures, cardinals, scissortails, etc. Not as many lizards and no snakes. I saw one feral housecat which took off when he saw me.
This is a very nice hike with shade, patches of water in the river bed and some longhorns wandering around. I got quite a few pictures and have included one of an adult MS Kite and two juvenile Kites.
NOTES
VERY IMPORTANT - The entrance to this portion of the park is not locked but you MUST check in at the South or North Shore gates and see if the area is open for hikers - hunting season starts soon and this part of the park will be closed to hikers. Be aware that I found quite a few crushed beer cans and spent shotgun shells so play it safe - make sure those irresponsible hunters who drink their breakfast, don't mistake you for their target.
Water and toilets are available at the North Shore gate check-in where you park. There are no facilities on the trail.