The four wheel drive worked fine. The 2011 F250 was steady as a rock and has been wonderful this whole trip. A few days ago I looked at my friend's hitch and notice it looked it had been changed. Apparently, he had a couple of inches cut off the bottom and when it was returned, the bolts were in different places lowering the front of the trailer. It probably compromised the WD bars and lessened the weight on the Bambi's single axle. I think that may have contributed to the fishtail. We have since readjusted the hitch.
I also feel the weight and the advantage of two axles on my 27' FB helped maintain stability. I never felt anything unusual but it was still scary. I remember I had a F350 with a Lance cabover camper on it and it maxed out it's total weight. I believe weight gives you an advantage (as long as you don't abuse it) in the snow as I seldom had to switch to FWD with that combination.
In over 30 years of owning a FWD truck, and only had to put chains on both axles of the truck when caught in a snow storm many, many years ago in the CA Donner Summit area. These days they just close the road.
The ability to follow instructions is highly underrated.