I had only towed a pop-up camper before my 42' fifth wheel. The only good thing the dealership did was sent me for a test drive with one of their techs driving shot gun. It helped calm my nerves a lot and I was able to ask a few questions.
As for turns- he said that until you get used to how it tracks, make sure you don't start your turn until your trailer's wheels clear whatever obstacle is in the way. You can then turn as sharply as you need. It really helped me get a feel for it without risking hitting stuff.
As for backing, like Jerry said - pull a little further past than you think you need before you start backing in. My very first campground after buying the camper, I was struggling getting into a site. This older fellow was walking past and as he passed my window, he simply said, "if it were me, I'd pull forward a little more." Given that I'd tried and failed 5 or 6 times by that point, I did it worked. Now I always pull further forward than I need.
