DCA will be different for you, so you could spend a day or day and a half there.
Disneyland is very similar to Magic Kingdom, but it may still be hard not to go there 2 days.
You definitely should go on Pirates, Indiana Jones (Dinosaur ride vehicle), and Small World - for nice differences.
If you are going 3 days, the Park Hopper may be an option worth considering to give you some flexibility.
The Parks right across from each other. DCA used to be the parking lot for DL.
If you stay at the Grand Californian (best, with private entrance to DCA), Disneyland Hotel, or Paradise Pier you can get in an hour early to Disneyland likely on Tuesday, Thursday, and Saturday - and early to California Adventure on Monday, Wednesday, Friday, and Sunday.
If you are able to do that, it makes the first 3 or 4 hours nice - before it gets too busy.
We were there last July, and that worked great for us.
Congratulations on your 30th anniversary, have a great trip!