You might enclose the trailer (trade flatbed on an enclosed model) to camp in, but still be able to haul ATV en route. Otherwise, why do you want to pitch the tent on the trailer? Aren't thinking of a mobile tent are you?? And, an elevated tent in very cold weather will probably be colder/windier than pitched on the ground, and you lose the trailer function of the trailer without breaking camp. You stated a flatbed trailer. Is the floor between wheels/fenders or a full floor over wheels? Modifying 10'x12' tent....because your trailer is maybe 8' wide?? Maybe, use two 2x14-12' rigged to quick mount/hinge outward (maybe mount in stke pockets on traiker?) to widen trailer to use full 8' tent width (fold down legs to ground or angle struts to support 2xs), with longer guy lines reaching ground. Pitch tent over fenders using fenders as low seats/tables/shelves inside tent?? Maybe the 2x14-12s double as trailer ramps for loading......tent floor extensions post-unloading/camping. Or, use your existing loading ramps as the floor extension...covered over if open rung type ramps. I've seen several rigs mount an in-bed pickup camper unit on a trailer with an ATV loaded/parked under the cab overhang section. Even seen a "tiny house" built for the trailer (with and without room for ATV) that sets off when not in use, similar to the in-bed pickup camper removal.