I think you are going to have a really hard time doing Epcot in a 1/2 day with a 4 year old girl, but if it is that or nothing, definitely do as much as you can. Epcot is by far my DD's (4) favorite park outside of MK. When she was 2 yrs 10 months we were there from open to close and did not have enough time, so both trips we took when she was 3, we spent 2 full days there. If your DD likes princesses, you can usually find Snow White (Germany), Jasmine (Morraco), Mulan (China), and Belle (France) in WS and normally the lines aren't too long. Usually, Sleeping Beauty (France) is out there too, but on our last trip it was Marie from Aristocats instead. Mexican Donald is also there daily for pictures in Mexico. We have also seen Beast, Genie, Aladdin and Dopey, although I hear they aren't out there as much nowadays. In addition to Katied's list (DD loved all of those, except we didn't do the
Norway boat because I thought it might scare her), my DD was tall enough for Soarin and Test Track at 3 and she loved them both. Those are both Fast Pass rides. Soarin is much milder than Test Track, so if you can only do one, I'd pick that one. DD thought she was flying just like Peter Pan!