Tires - I know one trip is unlikely to get you to swap tires out that are good in the snow, but it may be cheaper than a crash, and if you intend to do it regularly, get tires meant for mud and snow (and noise) vs smooth quiet freeway miles and miles and miles. Or instead take your 4wd/AWD vehicle and get a hotel (every powder ski trip I want to take the RV, I end up taking the truck and booking a room). People in Central Oregon that take their RV to the mountain regularly have AT tires.
https://tripcheck.com/ is your friend when driving the passes in Oregon, in case you didn't already know. Use the cameras and have an alternate route (via the Dalles vs Government Pass)
I have chains, have never used them on the RV. I also have the Anderson Rapid Jack (crescent shaped leveling blocks) to drive the inside rears onto to throw chains on (drive up w/ inside tires to get outside tires off the ground).
If it's icy enough to warrant chains on your front tires in order to steer, time to chill for the night and wait for ODOT to sand or cinder the roads.