Oh gee, I didn't do my math on that. WOW, that is much more than 3-4 hours!
Ah, you'll be fine. Do they have gold bond in Germany? LOL!
SpiritLifter the only advice I can give is know your horse, your equipment, the terrain, and the people/horses you ride with. Be prepared for the worst and hope for the best!
When I was younger I used to trail ride for up to 10 hours bareback with a halter and a lead rope. I live in the hills so the terrain is rocky, hilly, slippery, scary, you name it. So I really know more by feel and experience than any standard training or internet advice can provide. Best bet is to ride out with people that have 1,000's of hours on the trails to walk you through. One time I rode my horse up a rocky incline that only goats would attempt. My mare tried to turn back on me, the rocks were crumbling around her feet, we were slipping. Instead of freaking out and trying to micromanage her I sat back and let her do her thing. As soon as one starts yanking on a mouth, tensing up and throwing you off balance, accidents happen. Best to stay calm and give a horse it's head, or do an emergency bail like you mentioned! I'd rather walk home than be crushed, LOL!