Dang it! I forgot my 'horse hotel'. :) An overnight or short stay in a small field with a shelter for horses on long trailer trips.
Did you know horses can only get REM sleep while laying down?! Granted, they only need a couple hours a day, and it can be split up in short, 30-minute sessions, but if you're going on a 2- or 3-day trailer trip and it's just not practical to pull over and let your horse 'hand-sleep' (verses hand-graze... hehe) for a few hours, what else are you going to do?
It would be a nightmare disinfecting everything after each horse... but that's what meagerly-paid horse-loving barn workers are for, right?!