If I was to be going back out OTR there would be no doubt that there would be a propane camp stove in my truck. You can use charcoal but usually there is some sort of time issue starting it then waiting for it to burn down. When we did bbq outside we have used a little collapsible thing that worked off of regular black and white newspaper, worked good for alot of meats and was very quick.
I've seen some fullsize bbqs on the side of those big bus campers that just slide into the side of it before you drive an I think I've seen the same idea with the big custom sleepers. must be able to mount a fullsize propane tank somewhere an run a line to where u need, just turn tank off like always for safety????