I have a 1991 toyota 4x4 pickup and want to tow it behind my bus conversion. can i use a tow dolly?

You can, as long as you pull the rear drive shaft out. Or you can use a pull bar and flat tow it. If, and it should have manual lock hubs on the front, but still pull the rear drive shaft from the rear diff. DO not tow it with the trans in netrual, or out of gear.