I40 is fine in Oct. You will not have any problems with weather or campgrounds. You will need to return on I10. I10 is really the only route in Jan. Winds can be pretty bad in the West Texas region to AZ/NM border blowing from the South thu the West. You will want to start early when the winds are weaker and pull over for the day when they get too strong. We have encountered 65 mph gust between Fort Stockton, TX and Deming, NM. Lots of places to pull over and dry camp. You won't be alone as most everyone else will have pulled over also. Don't worry about it tho as you are planning a really fun trip.
rocmoc n AZ/Mexico