Since I am new here, but not new to being self employed I hate starting off with a critical post. If your start up budget is 200K and you sink all of that into the truck and smoker that you pull behind it then I must ask what are you going to operate on? 200K is peanuts in the business world. And that truck is going to run close to that.
Now for your truck. Have you ever been inside a Utilimaster chassis? How many people are going to be working in it at the same time? Your center aisle is going to be what maybe 26 to 28 inches wide at best. Putting a stove and flat top right across from your customer window is pure folly. You have a window person and a cook... They are going to be pretty tight up and butt bumping continuously. The first time your counter help bumps into your cook and goes off balance you are going to have a burn injury on your hands. Moving your gen set center chassis and your stove grill aft makes far more sense. Looking at your design I doubt that you have enough room to swing open the doors on your freezer and fridge. Your layout needs a lot more editing and thought overall.
Now let's take up your attitude.... IT SUCKS. You ask for help and then rain on anyone that offers positive advice. You can't be self employed and have an attitude like that. You will have a rep like Amy's Baking Company before you know it. I am not hating or denigrating I am just telling you that you need to change modes before you step off the end of the dock.
I wish you all the luck with your start up... But please mellow out and take the suggestions you receive better. Mobile food is a whole different animal than theme restaurant brick and mortars.
But then again.... As you said... You have it all figured out. You need to add some humility to that recipe.