Unless you've been very careful, checking and filling your battery's water levels before and after each trip and not drawing your battery down too far while you're out camping, two years is about the lifetime for a standard deep cycle, "wet" lead acid battery, but it's worth checking into other problems, too.
First, you have a Scamp
Delux, so I assume your trailer has a converter; I'd check the power breaker for the converter. The easiest way to check it is to flip it off, then on again.
Clean your battery posts and clamps. A little lead/acid build up on the posts can seriously reduce your battery's ability to accept and release charge.
As for the battery itself, detach it and take it to a Walmart, RV shop, Costco, or auto parts store. (Make sure your battery stays upright and does not tip over, otherwise strong acid will leak from your battery, leaving a spill that is very difficult to clean up (I won't go into the steps here, you can Google it) and which will damage anything the spill touches. What you're looking for is a "Deep Cycle" battery that is about the same size as the one you're replacing. There are two types you should consider:
1) Conventional deep-cycle "wet" lead-acid-water batteries. My favorite place to buy these is actually Walmart, because they are everywhere and have a two-year, full-replacement battery warranty.
2) AGM (Absorbed Glass Mat) deep-cycle or marine batteries are long lasting, maintainance-free, and hold their charge better than wet batteries. Unless you abuse them by discharging below 11.5 volts several times they should last five years or longer, but you'll spend two to three times as much buying one. Favorite place to buy: Costco.