If you've got plenty of time, I would recommend taking 880 north from the Oakland Airport, then 80 west (over the Bay Bridge) into SF. Then take 280 south to 85 south to 880 south, which turns into 17 south into Santa Cruz. From Santa Cruz, take 1 south to Moss Landing, then take 183 to Salinas. From there take 101 all the way to Southern California. When you hit 5, turn south and follow the signs to
Disneyland.
Great places to stop along the way - San Francisco, Santa Cruz, Gilroy (outlet shopping), San Luis Obispo, Solvang, Santa Barbara.
Of course, you could just go south on 880 from Oakland to Santa Cruz and avoid SF and the Pennisula to save time, or skip Santa Cruz as well by turning south onto 101 when you hit it.
Nice stops a little off the track - Monterey and the Aquarium, Hearst Castle, Morro Bay. Once you pass Ventura on 101, you could take 1 south and see the So. Cal coast.
You could take 5 on the way back north. Besides Harris Ranch, which is a steakhouse located at the 5/198 junction, Pea Soup Anderson just north of the 152/5 junction is a good stopping place. Both have several fast food surrounding them. There's not much to see along 5. Most of the larger towns of the west side of the valley (which aren't very large) are located a few miles off five. For a more scenic route, you could go up 99 and cut over on 152 or 120. This would add an hour or two to your drive however.
I've been all over central california, so feel free to ask any specific questions. I could also recommend several restaurants to eat at in various locations.