Backing in a 5th wheel is far easier than a TT if you use the "Z" Method, pulling square up to a site an then trying to back into an site is a disaster waiting to happen ...
You have to get the tail end of the trailer pointed into the site to begin with, if you do this then your on the right track to get the job done, take your time, check your clearance's an back slowly ...
The rule has always been the longer the trailer the easier it is to back because the axles sit back further thus turn slower an give you time to correct when needed ... Good example, try backing up a wagon on the back of your riding lawn mower, then hook up your truck or car to a 30ft trailer of any type, which is easier :)
Safe travels :)