Why even go over the grapevine? It is a rate race.
At Lost Hills on I-5 head east on 46 to 99. On the East side of Bakersfield on 58 is the Orange Grove RV Resort. There is a Shell at the exit before that(Weedpatch hwy) with diesel at the Truck Stop behind it. Easy in and easy out.
Then you have a nice scenic pull over the Tehachapi! Turn South at 14 and head to Palmdale. Do not take Palmdale Dr, continue South for two miles and exit on Avenue E and head East to 138. You will have a nice rolling drive to I-15 on 138. Head down the hill to I-215 and at University head East on 210, then onto I-10 like normal.
From the Shell in Bakerfield it is 206 miles to the Pilot at the West end of Palm Springs.
As a side note I-5 is getting bumpy again North of Lost Hills. 99 might be better from Stockton down. I cross over on 120.
Chris