Cliff & UFO's install solutions provide the best of both "portable" and hard-wired solutions. If the unit fried (which I believe it is supposed to do in a hard hit), you could unplug the input & output, then plug the two ends together. Take maybe 5 minutes for a perfect bypass.
W/that said, the SurgeGuard & Progressive units will drop the pedestal connection for low volts or high volts. What's maddening is when you plug in and the volts keep drifting in/out/in/out of range. You hear the xfer switch bumping on/off/on/off all night till you get up, go out, & shut off pedestal breaker (or unplug). Had that happen in Mexico where the transformers were potted high (all year) so when there was heavy air conditioner draw in summer the voltage would be in range. We were there in winter. So a 2-3 volt drift just hit the upper limit cutout for S.G. repeatedly. Still, the surge or way-low volt protection is nice.
Baja-tested '08 2-slide 36'
Alpine: The Ultimate DIY'er Project