A 16 oz can of Woody XXX paste wax will do at least 10 trailers. A little goes a long way and if you use too much it will take forever to buff it out and remove any swirls. You definitely need a buffer and it takes about 2 hours maybe a little less if you're fast.
On a new trailer for the trip home another option is the Woody Wax spray. This you apply with a clean cotton cloth then wipe off with blue shop towels, no buffing, takes less then an hour. This provides protection for a month or two. Then when you get home, wash the trailer then apply the XXX paste wax for 6 months protection. The spray wax acts as a mild cleaner and will remove light stains and oxidation as well as protection for a month or two. If you put it on over the XXX paste wax it will remove the paste wax protection.
After I got my trailer home and got the initial coat of XXX wax on I used it over a six month period until I noticed it getting some minor stains. Then I washed it, then used the spray Woody Wax which removed any stains, then put a coat of XXX wax on. Repeat every 6 months or so depending on usage.
It depends on the weather you get when you take your trailer home. I picked mine up in October and didn't put anything on for trip home. We only had a little light rain so we had almost no staining or oxidation. If you expect relatively mild weather the spray wax would probably be just fine. If you're going in winter and expect snow and road salt I would opt for the XXX paste initially.
Hope this helps clarify the Woody's Wax a little.