Anything that sits below the hitch will be fine. Just secure it.
I carry a generator, a toolbox and a few items in my bed. I used to carry ramps also. No problems when secured (multiple bungee cords work fine).
2013 F350 6.7 DRW SC Lariat
2011 Brookstone 354TS
Swivelwheel 58DW w/1993 GL1500SE