More and more, your success will count a lot on how marketable you are.
A combination ice cream/hot food truck is a great way to maximize your earning potential.  This kind of unit will allow products to be sold from morning until late night if you so desire.

Since the truck will be built to meet the strictest health code standards, you'll be able to also do a wide variety of events from construction site vending, private catering, parties, concerts and fairs and festivals. 

This will also allow you to work year round in the colder climates if you desire.