How long was 220 volts on the trailer before breakers tripped? If they tripped immediately, you didn't melt any wiring, as some post have mentioned, we hope. Anything plugged in to an outlet and "on", may not work. If the refer was on AC, probably took it out. Furnace is DC only, usually.
I would get the power right, turn all breakers off in the trailer, hook up power, then turn them on one at a time, and test things. Unhook the battery, so you can see if the converter is outputting enough current. Test everything, one piece at a time, lights, furnace, refer, microwave, television, AC, water pump, stereo, and everything else. Repair/replace what doesn't work, one piece at a time, starting with the converter. Lat thing is to rune everything on DC with the converter, and if it all works, hook up the battery.
Hope you weren't planning on camping over the 4th.
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic
2008 Work and Play 18LT