Using the M1008 for this? Do you have the troop seats in the bed? How about hanging some gear off of the seat backs? -Or paint that large black chevron on the door like the trucks used in the first Gulf War had? If there are other MVs in the parade maybe your CUCV could be placed somewhere in the middle so the viewing public gets the idea that the "chevy pick-up" in an MV as well. Like others have already posted, though, those that have served when the M1008 was in service will recognize it.
Remember to pull your PMs and check everything before you head out to the parade jump off point. Nothing more embarrasing then having a break down in the middle of a parade...
Good Luck,
Matt