Just like Mike this past Fall, I'm finishing up my 54"x18' dory and have started looking for a trailer. If anybody has any leads on a used one, please let me know. I live in Portland.
For my first drift boat, I purchased a gem with an R D Baker trailer. It seems the trailer may work well for drift boat number two.
It may be useful to get a quote from R D Baker (or other source) and keep this in mind as you search Craigslist or other sources. A new, well constructed trailer delivers in service.
A cheaper alternative may require a lot more maintain (and cost).
I have decades of experience of buying cheap and living with the consequences. I think the alternatives are worth considering.