Welcome to the Stovebolt Vince.
You have ten-lug hubs and should be able to find some of those 19.5 wheels on a box truck or maybe a motorhome. You'll also see very similar 8-lug wheels, so look carefully when you are buying.
Finding a pair of wheels to fit the back so you can move the truck should not be too hard. You may have more trouble finding wheels that will also work on the front.
