If you're only going one day then I would recommend you do
Disneyland and skip CA Adventure. We LOVE CA Adventure but you won't have time for both parks. It is spring break for Arizona and Utah, at the least, so the parks will be busy.
I recommend printing a map of Disneyland and figuring out what they have that the World does not. You'll definitely want to hit Pirates and Space Mtn. as it is different than the ones at the World.
I'm pretty hardcore DL so we'll definitely be arriving at open and trying to stick it out until close.

Would be great if all us pre-cruise-DL-goers could maybe meet up in the park and ride Pirates? Nothing like sailing with our favorite pirates before we sail with our favorite mouse!
If you are determined, and you really want to go to CA Adventure, I do think it's worth a visit. Screamin', a roller coaster, is pretty awesome!
I like a lot of the restaurants over in New Orleans Square. I've never been disappointed at any of the places we've eaten there.
But with that said, we normally get breakfast at the hotel and leave the park to have a late lunch/early dinner off site. There's the Anaheim Gardenwalk very close by and they have a lot of restaurants there. You can get more food, for about the same money you'd spend at DL, and it gives you a small break from the crowds! We always return to the park and we snack a lot. Dole Whips, Tigger Tails, Mickey bars (although, we may save the $ and get those from room service on the ship!)!! I also pack light snacks in our backpack since the kids normally ask for a little snack while we're in line.