You may not need to license your trailer, depending on state law. Here in Oregon, trailers under a certain size can go unregistered.
There are things you should know before you go boating on major waterways or the ocean. Navigation lights, channel markers, right of way rules, etc..
Get a book and study it, I'd say. Something like "The Official Guide to Small Boat Navigation" by Charles Farrell, for example.
Lots of people don't do this, of course. They just blunder about, getting honked at by angry cargo ship captains, running aground, getting tickets for missing safety equipment, and so on and so forth. Eventually, they may learn by hard experience what they could have learned with a couple hours of study.
Something to consider...
