Hi Warren,
I have run south on I-5 plenty, both winter and summer. For winter, know that if the chain sign is up, you have to chain up the motor home as well. If you are pulling a trailer, you will need to put a "drag chain" or trailer wheel chain on as well. Chaining on and off is a pain. Give yourself time to catch the weather window. Use your CB. Going south on I-5 use channel 17 in WA and OR, in California you'll find and equal number of drivers on 17 and 19. Going south, the advice to take 205 around Portland is good advice. No extra time cost, and better traffic situation usually. An option to I-5 if the Siskiyou mountains in Southern Oregon are going to be snowed in for a long time, 12 hours or more, would be east on 58 just south of Eugene, towards Oakridge, (commonly called the Oakridge-Weed cutoff) to 97 South, follow 97 south to Weed in California, and then get back onto I-5. It is a little bit farther, but less steep and generally less snow depth. It will all be 2 or 3 lane, not freeway, but in the winter, an awful lot of commercial drivers use that route to avoid chaining. Watch the weather (duh) and listen to the CB for the immediately near you traffic. You don't have to talk, but if Lorrie gets on the radio she will get answers. Listen for someone making the long haul, LA or SD and see what route they are using. Admittedly, the quality of long haul drivers on the average is not what it used to be 5-10 years ago, so don't count on them putting your chains on for you , or even being civil on the radio, but there are still some that are old school out there.
Wish you a great trip, travel safe,
Harvey
SleepyC :moon