Endurance hopeful here. ;)
MY boy's a ranch/cow bred QH so far as I know, so maybe we'll never be rockstars at it, but there's still a very long way to go before we max out our potential. So far we're still at 'longish trail rides,' lol, though we did do 20 some odd miles a couple of weekends ago with no pain, soreness, or trouble on either of our parts. Breaking into it s l o w l y.