5' will probably be long enough for most campgrounds with a "dump station". And yes, you only need a fitting on the trailer end of the hose. Where you may need a longer hose is at a "full service" campground, where there is a sewer inlet on your campsite. That inlet may be several feet from your drain, so you may want/need to purchase a longer hose as an "extension". If you use an extension, you'll need a "splice" fitting to connect the two hoses together. Most campgrounds with "full service" sites require a sewer adapter fitting at the other end, so the sewer outlet isn't left open while you're connected. I might suggest you also pick up a 45-degree or 90-degree clear connector. it's not essential, but it's very handy to have. It will allow you to monitor your sewage output. While that's not nearly as entertaining as your T.V., it does tell you when your tanks have emptied, if your t.p. is breaking down like it should, when your black tank rinse has sufficiently done its job, etc.
Hope that helps.
2013 Eagle 266RKS
2011 Ford F-150 w/3.5L Ecoboost & H.D. Tow Package