I agree with the suggestion to consider setting up a table at a farmer's market as a way to test what food items will be popular, and start with a food cart before you get tied to a food truck, If you get a cart, you'll need some type of vehicle to tow it to its operating location, but that also means that if the vehicle breaks down, the cart can still go out behind another vehicle. There was a popular local food truck that went out of business because transmission troubles meant he couldn't get to his customers.
You'll need to be tech savvy, because many jurisdictions only permit the truck to be stopped while it is serving. So you have to use social media to let your customers know that you're on your way, and have a line of customers waiting when you arrive.
I would seriously suggest getting to know some local food truck operators, and ask if you could volunteer to help out to get a sense of everything required (Don't forget you'll have to have clearance from the health department). It's more than dashing around on the truck, there's buying food and serving supplies, doing the food prep and cooking, doing the books, taking care of licensing, permits, and insurance, and cleanup.
I'm exhausted just thinking about it!
If I were going to try a food related business, I think I'd try to find some type of specialty item to make that I could sell to local caterers or directly to people planning parties, events, wedding, etc. I've got a co-worker who picks up extra money making diaper cake for baby showers (okay, I know that's not food, but you get the idea).