I bought Jayco's slide-out bike rack/cargo tray, and had it installed on the frame, below the back bumper of my trailer. I store my 35 gal. "Smart Tote" on that - tied down with ratchet straps while traveling.
2013 Eagle 266RKS
2011 Ford F-150 w/3.5L Ecoboost & H.D. Tow Package