Which tour are you referring to? If it's the Walk in Walt's Footsteps Tour, whatever you do, avoid Vincent (a tall skinny guy with moustache) as a tour guide. Half of our group bailed out because he wasn't very interesting, and a lot of the info he gave is stuff you can find in books and other sources. I think it would've been a lot better had we gone with the other guide (there were 2 and we split into groups). Also, if you do this tour, you can get 50% off if you have a Disney Club Card.
You don't mention where you're staying, but if you have the time, it's fun to explore the Disney hotels, especially GC (we stayed there and loved it). There is a hotel tour there which I thought was great. And Storyteller's Cafe has a great corn chowder!
DCA can be a lot of fun if you take the time to look around and study the attractiions beforehand. (One of my friends left after 1/2 hour thinking there was "nothing to do.") Soaring Over California is probably the best (and most popular) ride, and very unique. Be sure to do it early, you'll probably want to ride again! Then there's Californian Screamin', the rollercoaster, and the Maliboomer where you rocket up to something like 14 stories. The sunwheel is a giant ferris wheel, and there are some moving cars. Watch it first to see if it's for you...I know people who've gotten sick on it. I actually preferred the stationary cars because you are up higher. There is a film called "Golden Dreams" which I thought was pretty neat, and it's a nice place to relax. Grizzly Rapids is a water ride where almost everyone gets wet! Muppet Vision 3D is pretty much like WDW's, as is "A Bug's Life." I think those are the major things there. There are other rides and attractions as well.
Have a great time!