We did some brief trail work as well. When we trotted for any significant time, I got the "I'm going to curl up" response when she started to get too forward - I did lift one rein and that helped a bit, but not as much as I would have liked. On the trail we have fewer options - such as turning - although I should make more use of lateral work to keep her moving but controlled in pace. We need to do more work in the arena to solidify things, but for her the arena is a pale substitute - she's always more forward on the trail.
We'll keep on working on it, but I'm pleased with our progress - we'll get there.