You will need to check the
Weather.com once you are near the date that you plan on traveling. Going to the coast, you will avoid any snow, but might have morning fog until noon, and the afternoon fog can start at noon and last all day.
Normally I5 is open. But it can close for a few days at a time, afterall it is around 4,500 feet. But with good planning and being able to stay in sunny but normally warmer Grants Pass for 2-3 days, you will find that there will be a 3-4 day opening where you can get from Grants Pass to Redding without any snow or rain.
There are a few nice RV parks along the Rouge River. The most snow that I got in Grants Pass from 1971 to 1975 was 1" of snow in 1974. Normally it will not get nearly the snow that Washington will get. We had very few snow days as a child. . . .
Good luck!
Fred.