IMHO a surge guard is a must. You spent a lot of money on a nice 5th wheel, now you need to protect all the electronics inside. I personally haven't had any issues at the RV parks we frequent, but many of my friends have, and it only takes 1 time to ruin your day. I just purchased an Progressive Industries EMS 50 amp unit that I'll hardwire in as soon as the rig arrives. I looked at the less expensive units and heard horror stories about MFG support and several that burned up. Get a good one and it will protect against all the common issues you may fine, and a few not so common. Here's where I got mine...
http://www.makariosrv.com/progressiv...40v-ems-hw50c/. I had great customer service and it arrived very quickly.