Last summer we were on the WA/OR coasts. When we came home to Mesa we came south on I 5 and then cut over to Bakersfield ( also last month from Fresno) then 58 to Barstow, then 247 south thru' 29 Palms to 177 south to I 10 thhen east. Assuming there are at least 2 of you - as you approach the Phoenix area ( around exit 121 or so get over into the HOV lane (yes Rv's with2 or more are legal!). Sat in that lHOV lane all the way until you see the left (HOV) exit to 202 HOV. That take s you all the way to Mesa befor the HOV lane ends. Stay on 202 all the way around until the US 60 (Superstition freeway) exit. East on 60 to Gold Canyon and you're "home".
Another choice - from Barstow take I 40 past Kingman to US 93 then south to 74 (Carefree highway) about 15 or so miles south of Wickenburg. 74 east to I 17 ans south to the 101 east. Around to the 202 and east to the US 60 .