I do what Ford does, I cook for a few days ahead and properly cool and reheat on site. I have a mobile vending truck that is approved for use and vent the smoke from my cookshack out the roof from an exhaust hood.
For electrical, I either plug in on site if available or I have a HUGE deep cycle battery and powerful invertor that can run all my equipment for hours.
Good luck, you will love it.
Kevin:--Cookshack 150, 22.5 WSM, Mobile vending truck, Red Thermopen