I mostly only drive on mountain trails. We bounce the bike over downed trees, over huge boulders and navigate steep trails all the time! Making sure she is good with the bike bouncing around behind her is very useful. You can do this with trotting poles or small tree trunks at your house. If you have big rocks around then I suggest navigating those as well!
You may find that at times you need to get out of the bike to help her over different obstacles. Some of our trails are so steep I have to get out and walk while Zorro pulls the bike up the trail. This is something that is dangerous and frowned upon but should be addressed. You don't want to be in the middle of a situation and not have that as an option. To facilitate this I use 11' long rope driving lines. These allow me to walk along behind or beside the bike. I run the lines between my legs, sitting on the extra and allowing a bit to dangle behind me when I am in the bike. Don't let it drag on the ground! I like the rope lines because sometimes they get dirty and stepped on
I'll share a few videos of our latest drives here:
I'm making another video today of our evening drive last night. We did some difficult boulder strewn trails and roads.
I write a blog and share my drives on there as well! Here is a blog about trail driving:
https://www.theessentialhorse.com/post/trail-driving
If you are trail driving in the forest sometimes you may need to open gates. Sometimes you'll have to get out of the bike to do this. The other day the gates were all wire gates and I can't open those while staying in the bike. So your pony will definitely need to be able to stand quietly. Wrestling a gate AND a pony will be very stressful. The pipe gates that swing can sometimes be opened and closed from the bike. Here is a video link of one of my FAVORITE miniature horse drivers, Sue Mason, opening and closing gates from her easy entry:
I suggest figuring out how to have a halter on under your bridle. I had to remove the nose band so I could do that. BUT my boy drives in an open bridle so he doesn't really need the nose band. If you drive in blinders you'll need to keep that because the nose band balances and helps keep the blinders centered. A driving/grooming collar is a great option but you'll need to take the time to teach her about that. The pressure comes from a different place than it does with the halter, and can cause them to panic at first. (you can see this in the photo below, right behind this little mares bridle!)
I have a first aid kit in my bike pack as well. I also carry bear spray and my hand gun when I am in the mountains. But we have bears, wolves and mountain lions so I am just being prepared. I have two bottles of water, one in the bike water bottle holder on my bike and one in my pack.
I have paracord in my pack, small bolt cutters, scissors, a diapter and vet wrap and wound spray in my pack as well. I keep my phone on my person at all times. Just in case I am separated from my pony.
We have so much fun in the mountains around us. Most of the driving I do is in the mountain right behind my house. But I also haul 4 hours away to go camping with my friend Molly in a place that has literally 100's of miles of old logging trails and wonderful driving trails. The ponies do work pretty hard but the trails are so much more cart friendly than the ones behind my house!
I think you will have a blast doing this!!