My take is that a RWD pickup with winter tires is pretty near useless in mountain snow driving unless you put a LOT of weight in the bed. Like 1000 # or more.
Without heavily weighting the bed - - on flat lands, minimal amount of snow, maybe OK. Driving up mountain roads to ski areas, good luck.
If this question is a disguised "should I buy this 2WD pickup that I found a deal on, and can I get away with 2WD in winter if I buy snow tires" - - just pass, buy a 4WD.