For camping, I'm after, in order of preference:
1. A tradesman's trailer similar to this one:
2. A high-sided (approx. 500mm) 6' x 4' or 7' x 4' trailer with a water-tight lid.
It needs to be in good order and not immediately needing a rust treatment and painting (unless the price is very low).
I'm in the Taree area (Mid North Coast of NSW). For the right trailer, I'd be happy to travel up to four hours - but it would want to be good.