Re:Trailer vs cart??
If you already have the trailer, it's already licensed, and space is not an issue, stick with the trailer, especially in Florida, where thunderstorms pop up quickly - you're better off with everything under cover.
I worked a hot dog cart at The Villages for six years. Rain was a real problem (you have to shut everything down (the rain can extinguish the burners, so you don't want to leave them on), you have to get all the stuff you don't want waterlogged (napkins, buns, hot dog wrappers, etc.) put away; and you have to time it right — do it too early, and customers wonder why you're shut down when it isn't raining yet, wait too long and everything's a soggy mess (including you). With the trailer, I'm assuming you can close up the sides and take cover either in the trailer or your tow vehicle and wait out the storm.
The cart was a maintenance nightmare, too (in all fairness, it may have just been that particular cart, made by All American in Miami, and bought used).
Cart do have nostalgia on their side (Worksman in NYC even has wooden-spoked wheels optional on their carts!), but it seems to me the trailer is roomier and more practical.