I made a living hauling logs in the snow with my RV on site.Sometimes on the logging truck I had all the drivers chained with one single on the front to steer and just one set on the trailer..As for the RV,one set or even just one tire chained up also makes a big difference as well as a set on the tow rig and maybe even one on the front for steering...
It all depends on the situation as to the correct choice for each particular case.The biggest mistake everyone makes,including some over the road truckers,is not to chain up thinking I can make it.Good chains are a must traveling anywhere it might snow.
I here on the scanner almost every day now(when snowing) of semi's/cars and trucks/RV's and even tow trucks and bus's spinning out and blocking the road on Whitebird hill, just 5 miles away.Even had plow trucks off the road..Even a tow truck chained up spun out and needed help..
My point...Don't travel in the snow unless you absolutely have to and if you do,always have enough chains and don't be afraid to use them.
Personally, when I'm in an RV and it's snowing,I pull over and camp until it's over and the road crews take care of the road.