I've only done one domestic 1000k, but the big difference I noticed is that everything takes a lot longer on PBP, and the control times seem set up so that it's tougher to sleep for four or five hours at a time. I'm sure much of that is my inexperience. But I spent more than 25 hours off the bike, mostly just waiting for things: food, bathrooms, showers. I only slept about two hours.