The barebones of this idea are ok. It's all of the details that will kill
you. Have you ever run restaurant business? Are you an experienced short
order cook? When you say areas that sounds like a lot of licensing issues.
Each town or county will want various fees and inspections.
You are right that it will do good business for spring break and the 4th
of July, but the bills will keep coming during the slow times.
Why not make a deal with some sub shop and pizza places to do deliveries?
You can do that in a small boat and test the waters.

Dave M.