We boon dock in the mountains and tried to stay as close to 30' as possible when we bought ours. Wound up at 34+' but it worked well. Shortly after a friend bought a 40 footer. Too much.
Not sure if it would matter to you, but that horse trailer wouldn't go in many of our spots without dragging. Sits way too low. That's another thing we looked closely at when buying. Clearance and overhang. Some of the spots we camp drop off fairly steep from the road.
I guess it all depends on where you wind up going. Hope you enjoy the journey, where ever it may be.