I've learned that I never have a fuel odor problem as long as I don't load the toys hot. On the bikes and wheelers, the engine heats the fuel tank and pushes fumes out of the breather. Load them cooled/cold and there isn't a problem.
My dirt bike can sit in there over a week without issue. Load my FI street bike when hot and it'll stink...
On our last day of riding, we shower and clean up, then load the bikes last right before we leave.
2005 2500 Cummins/48RE/3.73, QCLB, 4wd, BigHorn, Edge Juice w/ CTS + Turbo Timer,Transgo Shift Kit ISSPro Oil and LP pressure gauges, GDP 20/2 filters, Custom Diesel Steering Box Brace
'10 Forest River Shockwave Toy Hauler 21'
Honda EU3000I Genny