My experience is that "off road" and "spinner" don't mix.

Spinners are designed for, and are terrific at the airport and usually at hotels, - anywhere there are smooth, clean, very flat surfaces. Outside of these ideal conditions their performance characteristics deteriorate considerably, and on "dirt/grass/uneven pavement" spinners become a complete PITA. Also, when all those wheels get fouled up in the dirt/grass/uneven pavement and you then roll it on a smooth surface it will be more annoying than a worn out WalMart shopping cart. You will likely end up carrying it to the nearest dumpster.

For your intended application, the fewer wheels the better. If you absolutely need wheels get a roller board, if not, use a backpack.