Hi Andy,
I was trying to keep my build low budget. I was fortunate enough to have somebody give me a broken down jet ski trailer that I was able to fix and modify to meet my needs. Since the trailer would be garage kept, I was not worried about protecting the boat from the weather and I felt that an open trailer was OK. I rigged the trailer so that I can mount multiple engines on it , strap gas tanks to it and have an attached tool box. It has worked out pretty well for me. Plus, it is light enough that I am able to pull it with a vehicle that has a low towing capacity.
Quite a few racers have cargo trailers, which are extremely convenient, but more expensive and heavier to haul. Frankly, I wouldn’t mind having a cargo trailer, but I am OK with my set up and will probably stick with it.
I would recommend visiting a race or two to get a look at what setups people have. You might get some good ideas. Good luck. I look forward to seeing you on the water!