We've traveled I-40 on several occasions while returning from the mid-west and almost always we've encountered winds through NM and some in AZ. During this time of the year you could encounter snow in the higher elevations so I would carefully check weather conditions along the route.
Many folks get permission from Wal-Mart management to use their parking lots for overnight stays where it's permitted, usually very safe.
If you're a Good Sam Member, you can go to their website at: Good Sam RV Club
where they offer travel planning tools.
We often use either Woodall's or the Trailer Life's directory to find RV parks along our travel route.
Like you, we usually limit our daily travels to around 350 miles or a bit more if we get an early start in the day.
If you'll be in that area for a while, be sure and try to make the Quartzsite scene.
Have a fun safe and trouble free journey....