It works great. I get to cook out of my trailer, load everything up and drop it off. Must have clear comms with the customer on what your bringing, plastic wear, paper plates, condiments etc.
Cooking on site, is not really cooking on site, I'll start a fire and get smoke in the air but most of the big meats I cook the day prior, they are being reheated on site. Ribs and chicken a bit different.
Network, Network, Network... Feed the neighbors, friends and family and have them tell two friends and so on and so on. Social Media helps, website is a must.