There was one "greatest hits" songbook that I was fortunate to pick up 25-30 years ago, but I don't believe it has Trip to the Fair. I can check when I get home. However, even if it did have the song, it wouldn't have the entire intro. I remember buying the book because it had all of Prologue transcribed fairly accurately, but that was really the only song with all of the piano parts. Most upsetting to me was that the intro to Running Hard was completely skipped. To this day, I've wanted to play that, but I just stink at figuring things out by ear (which is now compounded by some serious tinnitus and hearing loss). Props to you for pushing through and trying to figure out Trip to the Fair.
Tom Brislin has played with Annie recently, I believe as Renaissance. He may be able to provide some pointers if you can reach him...