Mine doesn't mess with any of the fencing... She got zapped once and aside from eating off the ground on the other side of the fences, she really doesn't sit on them or damage them in any way. She DID almost knock down her stall wall a few times from deciding it was a scratching post.
I wouldn't worry about a trailer, like I mentioned, mine at 17.1 fits in a standard sized featherlite without being cramped. I believe Sundowners are the same.
Although, after seeing a few other Percherons on here, my girl looks to be a little short backed in comparison. It's definitely something to give careful consideration to, but in my case, it worked out perfectly.
BTW: Yoder Farms (Duke) was one of the videos I watched when I was researching the Percheron breed before I got mine. Duke is an amazing horse
ONE horsepower, TWO-THOUSAND lb/ft torque... If it doesn't weigh a ton, it's just a horse....
Percheron, Percheron X Owner