I Rolled my Sotar one time, and it sucked. I grew up rolling up Riken IK's and rafts up to 15' long, and they were easy. For my boat, I think it is much safer to keep it inflated as much as possible. It has been from Oregon to the Colorado on a trailer with carpet, the Rogue a few times, the John day a few times, etc on a trailer. I check straps and pressure when on longer trips out of the Willamette valley, and haven't had any issues. I think I'd have more issues with folded material possibly rubbing a hole than a nice long tube sitting on a smooth, clean surface.
Wishing I was on the river instead of surfing the web...