I would think a Smokey Joe would be your best bet. I have had the little propane gas griddle for tailgating, and that worked pretty well for burgers, sausage, fajitas, etc. but it's basically a hot plate.
Now since I am more into smoking than grilling, I have considered some of the new smaller smokers that do just like Janet says, slides right into your trailer hitch receiver. Looks like Gator Pit has one that I might need to try out this football season. The only thing is there is limited space tailgating these days, and it would have to stay with the vehicle.
But if I can keep my problems limited to that, I am in pretty good shape! LOL.
Backyard Gator Pit