In the PAST, what would happen is that I would try to get her to straighten up by using the right rein to ask her to bring her head back around. I think that was sort of the opening she was looking for, because she'd quickly go from being hyper flexed left to saying, oh thank you for opening that door, you want to pull me right, I'm going to REALLLLLY go right and basically put all my power into spinning around that right shoulder and turning back towards home. She doesn't spin around and bolt, she spins around and continues walking along as though she was asked for a quick turn, which obviously she wasn't.
Lacey would do the same thing!!
With her, the trick ended up being just riding her forward. Giving her a solid kick [or a smack with the crop if a kick didn't work] seemed to do the trick if she managed to get her head around. Of course, there were sticky spots [she had specific spots where she believed we "needed" to head home] but I realized that mostly it was MY fault. I'd get so "oh this is a lovely trail!" and she'd do her head thing as a sort of "hey! I'm here too, buddy!"
If I stayed conscious as a rider, kept her impulsion up, I found she would rarely even try. The minute I let her get ploddy, the more she'd start taking charge of the ride and swing her head around.
With the trying to lead/getting prancy, if she's anything like Lacey, it's just her inexperience showing. Lacey felt safest when she was leading so, as a green trail horse, I generally let her lead [I suppose it's something like being backseat driver? Haha She wasn't sure the horse in front could handle whatever might happen, but she knew
she could handle it better.
] since she was a perfect ride in the lead and the people I'd generally ride with loved not having to worry about leading.
As she gained more experience on the trail, she became fine anywhere in line - no fighting [actually, she got SO comfortable that getting her going, in company, became an issue hahaha]. My only guess is that, at first, she wanted to see the scary stuff first and didn't like feeling blocked in. Later on, she realized that she wasn't missing much so she might as well take the easy job.
Same with prancing - it's something that just went away as she gained confidence on the trail. In Lacey's case, prancing directly correlated to nerves which directly correlated to energy. SO, back when she was green, I'd take her out and let her run away from home. We'd go out for hours and she would be happy to plod home. Again, as time progressed and she became more confident on the trails, we could have rides that were all walking and no running. But, at first, we did some walking, mostly trotting, and some long stretches of cantering. [somewhere in this transition phase, I also started using a pelham when we went out on the trails - I just kept the curb rein handy "just in case" as my emergency brake, and rode on the snaffle rein. But, that way, I knew I could stop her if she got overly excited at any point]