It is definately true that there are a number of threads on this forum, including links to customizers, advice for do-it-yourselfers, etc. Peruse carefully. Also, search "mobile espresso" and other combinations, and you will find people in the business.
Regarding the inspection routine, you should definately plan to submit blueprints in advance to your Health Department for approval. This is called Plan Review and is the same as if you were going to open a restaurant. which in fact is what your truck will be. Expect to include a hand wash station, for instance.
One thing I would encourage you to think about early is maximizing the high-traffic, stationary venues. Driving around routes, selling a latte here and there, is a low return on the gasoline expended. The cool thing about a truck is that you can drive it to where there are hundreds of people - your sporting event idea. Pick up your County tourism package and see how many festivals you can find.
Another thought: don't be afraid to limit your menu. Since the truck can be expensive to run, don't have lots of items you make small margins on: a shop can do this because they have room.
Just going to your County Health Department website for Food Manager certification should be eye-opening. Your truck will also need a commissary - inspectable, approved water source, vector control, three-compartment sink. A lot of truckers make arrangements with a local deli, bakery or restaurant to refill their tanks and clean up blenders, pots, etc. Offer to sell their doughnuts.
There may be some slack counties out there that aren't as particular - but then you might have trouble going to nearby counties for permitting. The most populous counties will have the most potential customers and the tightest restrictions.
I second the notion that mechanical competence/confidence is a bigger item here than in other coffee businesses.
Good luck. As with any business, there are people who get overwhelmed, and people who do very well.