Many folks on this site have suggested picking up a 50Amp male/30Amp female "dog-bone" type adapter, as well. Because most trailers have 30A systems, the 30A receptacles at campgrounds can get worn and loose-fitting. As a result, the connections can get hot and damage your shoreline plug. Many folks will use the dog-bone and plug into the less-worn 50A outlet, instead. You'd then plug your 30A EMS into the 30A side of the dog-bone. You can find them at CW, Wally's, and most big-box hardware stores for around $20.
Just passing along the suggestion.
2013 Eagle 266RKS
2011 Ford F-150 w/3.5L Ecoboost & H.D. Tow Package