Ahhh, Powell's. Solvang, Modonna Inn. All wonderful places. We do the drive between S.Cal and N. Cal a few times every year. We also do the coast drive from SF to Oregon on occasion (we usually take I-5 but opt to take the coast when we have time). Some places north of San Francisco would be driving through the Redwoods (AMAZING!), Mendocino/Fort Bragg has lots of cute inns (although some have child restrictions). Once up in Oregon, there are several cute little towns and lighthouses along the coast. Florence and Newport come to mind. I think the Sea Lion Caves are just north of Florence. If you golf, you must stop at Bandon Dunes.
Up in Washington (this might be a bit off track) is Poulsbo/Bainbridge Island just outside of Seattle. Beautiful.
Overall, it is a beautiful drive. I hope you have lots of fun!