Hey there Java! A coffee cart sounds like a great idea, but you''re going to want to check with solicitor codes in the area/building in which you''re wanting to set up.
I''m pretty sure that NYC stopped providing permits for the carts years ago, and now renting is illegal. Those who do find a loophole are hit with massive fines for silly things. The New York Times ran an article on it last summer that you may want to reference.
Of course it may be that things where you are aren''t nearly as difficult. Should you get through all the red tape, my only suggestion is that if you''re planning to be outside, you may want to take the elements into consideration; things such as any effect humidity may have on the quality of your espresso shots, direct sunlight to the life-span of your syrups, etc may seem mundane now, but could have a bearing on the quality of drink you provide.
Good luck, and welcome to the coffee world!
