From SA headed West- I- 10 looks like a natural...but don't. stay away from interstates unless you are in a hurry.
we are coming into snowbird season in AZ and there will be many boondocking on public lands- esp around quartzite.
( you will spot many license plates from Alberta, Saskatchewan, Manitoba, Michigan and Minnesota!)
some travel South into baja- rock point/puerto penasco, or san felipe
I really like rt 60, which you would have to go North to get, lots of small towns and mom and pops- it IS the way we mythologize rt 66...it just doesn't have song.
coming across western NM on the high desert and into AZ is really nice. you'll be at elevation so it could be cool up there.
get out a map and some crayons and start looking at various routes and destinations
mike