>>795867dont know where you are but you dont need to register it unless it has a motor.
those sun dolphins are made really cheap. thin plastic hull. And if youre a bigger guy a SINK will be a pain in the ass for you. a SOT is really what you should be looking for but its understandable if you live in a cold climate.
Do you have craigslist in your town? Lots of deals to be had there.
trailer...harbor freight cheap fold up trailer. add ply wood and some tie downs and your set. What is a swivel hitch? do you mean a ball hitch?
try the kiss method and dont over complicate your yak. take it out without any of the shit on it and fish then figure out what you need. A crate works well with SOT's not so well in sit ins so you might try to figure storage options that work in tight spaces.
You also forgot your most important purchase to make and thats your PFD.
Watched a grown man have a complete meltdown on the beach when they pulled his dead teen aged son from the water who capsized in the kelp and wasnt wearing his pfd..I told myself that day that I dont care how much they cost im getting a good one. you should too.