When I bought my 200 Osprey (also a 1996), it came with a single axle galvanized trailer. I mostly towed local, but also took it to the Keys once (~7 hour trip IIRC). I had no problems at all with the trailer. But if I was buying a new trailer, I would probably lean towards a dual axle.
If all goes as planned, I will be picking up a new trailer for my flatback this Friday. I went with an Owens and Sons (Slide On) trailer based on feedback from fellow member Aaron (Aswaff400), as well as their great reputation on other forums. I initially started off looking for a used trailer, but based on the prices of decent used trailers, plus what I figured I would need to do to get it set up perfectly to my hull, I decided that spending a little more for a quality trailer would be my best route.