There a lots of options out there. On some of the ranch trucks and some trucks that are abused pretty hard, they've had problems with the spare staying up under the truck. Sometimes we move the spare to the bed, but for some that's not an option, so... ... In that case, I drill through the upper bracket, next to the winch, and install a 1/2" or 9/16" bolt(if the bed's off) or an all thread rod that's long enough to come down through one of the lug nut holes, and then put a nut on it. The rod is drilled so a lock pin can be installed to prevent the nut from backing off or a pad lock to prevent theft. It's somewhat of a PITA when putting the tire back up, but it's better than losing it on a dirt road. I also usually tack weld the bolt at the top to keep it from rattling or coming out. It's a pain to line up the rim with it moving all over the place, sometimes. A small rod can be welded on the nut under the rim so it can be loosened by hand, if need be, or a large washer so a lever can be put inside it to turn it.
If you do it this way, be sure you use two wahers against the face of the rim to keep the nut from working against the seating face of the lugnut. You can also find a 9/16 all thread or bolt that is the same thread as your lugnuts, and just use a spare lugnut.