When you go to the MTO, just tell them you need plates for a homemade trailer. Don't have to pay tax if the trailer's homemade. On the application, under color, put BLACK. Go home, use tremclad black, paint the trailer. It is now homemade!! Worked for me, and I had a brand new easy hauler(2005). (bought 14.5' boat w/ 9.9hp without a trailer). Why pay tax if you don't have to. If you ever sell the package, the new owner pays the tax. ( If he does'nt know about this!)
As for the rest of what you need, just a boaters card I think. Oh,,, and a fishing rod!!
BTW, I was pulled over twice on the 400, while towing, and they didn't ask to see anything regarding the boat either time. (trailer i mean)