I am guessing that your food truck is already built and so the equipment you could use is the equipment you have. If not, and you are lucky enough to be at the stage of ordering new equipment, get a commercial Combi Oven. They cost $8,000 to $10,000. Next best is a convection oven, for even baking. It takes 1 hour to bake potatoes at 400°F. A conventional oven takes 10-15 minutes longer. The potato is fully cooked at 210°F, but many operators take them out at 185°F and put in a heated holding bin (like a bread warming drawer) as they will continue to bake.