Or, to put that another way: the true cost is real estate. Don’t try to run a cafe. Find a pretty outdoor area where some property developer kindly built commons seating on their own dime, and drive a coffee food truck up to it.
Most places with high demand like this also have prohibitions (or limited parking/operating permits) on things like coffee trucks, in my experience. Another issue with our prohibitive land use practices in north america.
So maybe find a pretty outdoor area where there are lots of tourists.