I've catered a couple of weddings and a few other parties, not really professionally, but for freinds relatives. A couple of problems that I ran into: smoker(s) size vs party size. If there's 100 guests, and you can only fit 10 racks of ribs, it better be an anorexia anonymous party. Pulled pork sandwiches, sliced brisket flat (sliced on demand), sausages, are good choices, IMO. Filling, (anything with bread is good gets em full, bread is cheap) fun to eat and easy to cook a lot with limited space.
Another thing is sides, tater salad, cole slaw, beans, or whatnot. Keep them simple and traditional. Most folks have no taste, just because you like it doesn't mean everyone will. One couple at a party told my brother "we love your cole slaw, its actually even better than KFC's!" A dubious compliment, that. We'll take it though! Good luck, and welcome to this fun forum!