Maybe a bit late to the post but I just had my 1st meeting with health dept. yesterday to discuss my Non-Profit Food Truck, Concession Trailer, Catering and got all the answers I needed to start. Was told "It's all about the menu"! Build the rig based upon the Q and sides your cooking, the volume your selling and goal you need to meet financially everytime your open!
My "Q-Truck" is my commissary so it needed the ability to store, prep, cook and sell day to day. Water, # of sinks and waste storage/disposal is huge. Power to sustain refridgeration without a lot of exhaust and noise was another consideration!
Because I am choosing 2 FEC 120s for the truck (for cooking, as a conventional oven and as a holding/warming cabinet) I am able to use a Meadowcreek TS 500 and BBQ42 cookers in the trailer for large events and get by the NSF rule!
The truck can serve 300-500 "meals" a day and the trailer can get me to 1200-1500 if I need to! And it's all for a bunch of great Charities (I get to make a living too)