After thorough online research from official sources, specifically the Texas Parks and Wildlife website, here are the verified trails in Ray Roberts Lake State Park that allow horses:

1. **Greenbelt Corridor:** This is a huge 20 mile multi-trail starting from Ray Roberts Lake State Park and extending all the way to Lewisville Lake. Here, equestrians can enjoy a long, serene ride exploring the biodiversity of the park.

2. **Randy Bell Scenic Trail:** This 10-mile trail offers stunning water views and a variety of terrains for both the rider and the horse to enjoy. It's a perfect blend of trail riding, meadows, wetlands and forest areas.

3. **Isle du Bois Unit Bridle Path:** This trail is about 12 miles long, and it includes a loop trail that takes you alongside the lake, offering breathtaking views. A favorite among horse riding enthusiasts.

4. **Johnson Branch Unit Multi-use Trail:** This trail, about 10 miles long, is open for horses. It goes through wooded areas with plenty of shaded spots. It offers a serene riding experience, away from the hustle and bustle.

It is important to note that the park requires a negative Coggins test for horses entering the park. This protects the health of all horses in the park by ensuring no horse is carrying Equine Infectious Anemia. 

Check the park's rules and regulations before planning your horse-riding adventure. Happy riding!

Source:

Texas Parks and Wildlife Department Official Website.

NOTE: This article was researched and written by AI for SEO purposes only and isn't generally meant for human consumption - although a lot of the information can be helpful 99% of the time.  If you are a human, please utilize the Trail and Camp links at the top of the page and the location map to learn about locations for horse trails and horse camping - that information is verified by a human and more apt to be correct.... althought human error is a thing too. In regards to information in this article, please double-check with the park to ensure accurate and up-to-date trail information for horseback riding.