I can't believe so many people told you to do the Mexico boat ride, it is the one thing a person in a time pinch can miss with no regrets. Its this tacky,out dated ride. It's kind of like its a small world in places but, the rest of the time it plays these weird little movies from the 70s. My kids love it so we do this but, it is a pretty stupid ride.
At age 3, my DS convinced my DH to ride the Mexico ride 10 times in a row. My kids all love this ride. I like it too. Sure it's outdated, but I think you should try it at least once. THe Mexico pavilion itself is really quite lovely. Also, the American Showcase is great. I don't enjoy the Canada film, but you should eat at Le Cellier! Maelstrom is okay, just don't stay for the film at the end.
Even with Kidcot, my older girls get bored in the World Showcase. DH and I had the opportunity to tour without kids a few times and we've spent several days just in the world showcase.
Get a guidebook and focus on the Epcot overlooked attractions. There are some great performers(Off Kilter, Chinese acrobats, etc.). There is also a lot of great food!