The 40 is a lovely drive, a guess a lot depends on your allotted time. Albuquerque has a beautiful old town area, you pass the Petrified Forest NP, on to Flagstaff and William, we love Williams as a basecamp, staying at the Circle of Pines KOA. Only an hours drive to the Grand Canyon, or 30 minutes south to Sedonna. Swing up to Las Vegas if you have the time. Then on to LA. Yes, you might get snow, we did in late March last year, just a dusting, but enough for us to stay an extra day in Williams until the weather cleared. The 10 is not bad either, though it has been more than a couple of years since we took that route. You have Benson, Tombstone, and Tucson. In Tucson you can visit the Sequoia NP, old Tucson, Tumacori (not even close with the spelling). We lived there four years, lots to see...after you see it the place is boring.:)
Happy Trails.