I started using this just a few weeks ago. Danby Dehumidifier ADR30A2G
It does a great job removing humidity. It will take the relative humidity in my trailer down below 40% easily. It removed more than 2 gallons of moisture the first day I ran it in my trailer. (had a leak with wet floor) It has an external drain, so you do not have to tend the drain bucker. The down side: it gives off heat inside the trailer (as any dehumidifier will)
Make sure that the unit you get will come back on after the power goes off. I bought a prior one from Sears that does not.