Thule makes 4 sizes of the Evolution cargo box.
Before I purchased one, I laid everything out on the garage floor, then measured to see what size I wanted.
Pete J asked for a drawing of my layout. I scanned a crude drawing into my computer ... but can't find it now ... so I'll
paint a visual:
In order, front to back:
.....large rolled piece of outdoor carpet ...1 folding chair .. 1 sm table
Hoses->5 Gallon H20 Tank->5 gallon H20 Tank->15 gallon Blue Tote
..............3 folding chairs .... 1 large folding table .........................
Hope that makes sense.
We also kept our dirty hiking boots and a shoe scraper up there.
As I said, anything that could be muddy, stinky, wet, or otherwise obnoxious (and no, I don't ride up there!)