First competition/vending event

First off, I want to thank everyone for all the great advice and sharing of experience.
After two years on a waiting list I just got word a couple days ago that a spot is open in my new home town Pigout. Small event with 15 entrants and a combination competiton/vending event where you vend for the festival and people's choice and still turn in for 6 judges.
I am trying to figure out all the groceries I might need over the next month to prepare, but am anxious to see how my bbq rates amongst the locals.
Any of you have experience in the type of combination event that can give me a heads up on things I will encounter.
Wife and kids will man the stand and I am focusing strictly on the smoker...hopefully.

All the conversations I have heard about the event is that everyone runs out of food around 3-5 on Saturday and event is advertised till 10. A couple of co-workers are in it and say they have never made enough to sell the whole time it was open. I am not real concerned with pleasing crowd with quality of que, but I'm more apprehensive about getting scorched by judges.
I'm just excited about getting a chance to enter and have a little fun. A trophy would be just a little bonus.