[watahyahknow]

i wouldnt leave the aloys under there even if you wrapped them in plastic i would rather have some old steel wheels to put under there during the hibernation .
it not only the fact the aloys will go dull over time and will take some time to polish again when a tire is loaded for a couple of months standing in one spot it will get a flat spot that you will feel when you drive the truck again next spring usually it will stop after some miles but if there not under the truck it whont happen

couple of things ive seen done to classics here when stored inside is topping off the fueltank to prevent rust above the level of the fuel
putting the car on jackstands to relieve the suspension and the tires
mottballs on the seats (when there made of jute or wool)
a moist eater/dehumidifier (dunno if there available in the states they work the same way as those little bags with pellets found in electronic packagingboxes ) in the cabin
vaseline on the doorrubbers and some graphite in the locks and a squirt of light oil in the cylinders
some of the guys putting there oldtimers to sleep are verry serious or plain hairsplitters/nutcases , i've seen them put cars on a lift and dry it with a towel and hairdryer after driving it in any rain .............there wives must love them