I have never done the GCH tour that sounds so fun I need to do it next trip.
I second the Gallery tour if a CM has time they will tell you great information and also show you design drawings that are on display about how the apartment would have looked in use. Also they usually have great displays up there to see anyway.
This apartment was actually designed for VIP's and actualy had a private entrance to Club 33 (blocked now). But they will show you old magazine photos of the Family used apartment that is on Main Street.
I also want to add that you can get lyrics for all your favorite ride songs up in the gallery so you can stop singing the famous POTC "La, la, la, lalala..." version.