Hey guys,
After about two years in the making, research, selecting a 5'er, obtaining the proper license (Commercial Class A combinations with double/triple endorsement), rear camera installed, and having a hitch welded on the rear of the 5'er I finally doubled towed for the first time!!! :C
Super easy, kept it 60 mph and just cruised. I could feel the boat bucking the 5'er a little more than normal, but only on real rough areas or elevation changes (like over passes).
To all the nay-sayers and weight police: I was within all of my weight limits of the vehicle, king pin, and cargo carrying capacity. Drove very well and the boat tracked right behind the 5'er. My 5'er sits a little nose high, once I get that fixed I think it will handle even better.
Current: 2017 Winnebago 31K
(Sold): 5th wheel: 2015 Heartland Sundance XLT 245