I don't see her as too "forward" for trails AT ALL. (You should see my Missouri Fox Trotter! Some of us find forward horses fun!) Gaited horses, as a whole, are often quite forward. Nothing wrong with that. That's how you cover some ground.
What I DO see is a gaited horse being ridden as an english style horse, trying to be forced into a frame, and posted on to boot. The horse does not look happy. If she does have a gait, she is being forced away from it. Like someone trying to make a lefty use their right hand. Maybe you can force a lefty into using their right hand, but why not go to a horse's strengths rather than their weaknesses?
I think a change of riding style will do this mare WONDERS and help her relax and learn to gait. I hate seeing her forced into a frame. Sell her to a trail rider and let her strengths shine!
As for price? Well, in our area probably anywhere from $500 to $3500. A good gaited horse, set in their gaits (which this one is not) will bring the higher end of the spectrum. Heck, I've known people who have paid a lot more for gaited trail horses. Going out of state, paying tons of money, way more than $6500. But I don't think this poor horse ridden incorrectly for her breeding is of that caliber....yet anyway.
I got my lovely Fox Trotter, who isn't set in her gaits but more fun than a barrel of monkeys, for $500.