if you are serving 2000 people over a 6 hour period, that averages out to approx 330 people per hour, or 5 1/2 people per minute, or 1 customer every 11 seconds.
Most trailers are limited in size, and have only one or 2 serving windows. Trailers are awesome but become bottlenecks due to their size and working area. I think it would be almost impossible to serve that amount of people out of a trailer alone. If 2 more stations could be set up to serve from---it would lighten the load on the trailer.
Things kinda depend on what your local Health Dept requires, or if they will even check to see what you are doing.
That amount of meat is going to require quite a bit of holding area also. Brisket and pulled pork can be cooked in advance----but vending is a guessing game and you can either run out, or take home hundreds of pounds of cooked meat and no money.
When vending large events I like to cook tri tip. I like brisket better than tri tip, but tri tip cooks quicker and can save you if meat supplies start geting depleted.
Vending is vending, catering is catering and competition bbq is competition bbq. I cook differently for each purpose.
When vending I usually use an open Santa Maria style pit---I know that it is not smoking, however an open grill will outsell a closed smoker every time. People buy with their eyes----an open pit will draw a crowd faster than a closed smoker. At many vending events I cook in a large smoker, but still keep an open pit going with meat on it for people to see.
I would suggest figuring out how to use what equipment that you have to be able to serve the optimimum amount of people in the shortest time. If you are able to do so, I would set up a seperate condiment table to let people make their own sandwiches --and just mass produce plain sandwiches. Good luck--if I was closer I'd give you a hand.----------Leonard