If you're going to go out Hwy 229 on the way (the section south of Creston is the good part). Be sure to start by taking Pozo Road to HuerHuero Road to Hwy 58. Left turn on 58 and you're right at Hwy 229.
I personally wouldn't want to miss Hi-Mountain Road (dirt from Arroyo Grande to Pozo) but you are starting in Morro Bay and mentioned wanting to avoid dirt roads.
Under the unlikely situation where you can't get through the base, just continue up Jolon to King City. Then just short stint on 101 to the roads leading to Arroyo Seco and Carmel Valley Road (another nice ride through the hills back to Hwy 1).
I also like the inland routes (Indian Valley/Peachtree, Hwy 25, etc.) - you might want to give those a try as well.