For a nice relaxing drive go through Yuma and up 95.
Nothing wrong with 8, 111, 78, etc up through Blythe but it's much more demanding of your concentration along 78 - - being a lot of two-lane travel with narrow shoulders in places. And some drop offs into deep gullies here and there.
Thru Yuma seems to be about 15 miles farther and probably well worth doing unless you'd just like to be off on a rural road up to Blythe.
EDIT: Be aware of high wind on I-8 east of Alpine today.
95 Winnebago Vectra 34 (P30/454)