The Backstage Tour was originally a two-part attraction. Trams were originally boarded behind the Animation attraction, and they would then take you back through costuming, the greens department, then Residential Street, the boneyard (which has been added to slightly over the years), through Catastrophe Canyon, and then past New York Street. Guests would then get off at the current loading area which lead them into the Looney Bin from WHO FRAMED ROGER RABBIT. At this point there was no admittance to New York Street, nor was the Honey I Shrunk the Kids set built at this time, and the walkway running from the tram exit to where the Little Mermaid show is now was at the time closed off (only studio personel could go back there).
At this point in the attraction, you could loiter around the Studio Catering Co. area for as long as wanted before taking the second part of the tour, which began at the special effects water tank (with the original pre-Pearl Harbor show). You would then walk around the tank and enter the special effects workshop (with Johnny 5, etc.) and witness a short video about the train sequence from ________ Tracy. From here you entered the blue screen studio, where two guests would climb on the bee from Honey I Shrunk the Kids.
Next came the sound stages, where you would walk in the corridor above the stages. The conclusion of the sound stage area included a video on recording sound for movies (can't remember who hosted it), and a short video on editing (hosted by George Lucas, C3PO, and R2D2), and after that you would then watch the Bette Midler "The Ticket" film and walk through a stage housing all of the props and sets used for it.
The conclusion of the whole tour was a short fifteen-minute preview up upcoming movies (hosted by Michael Eisner) that took place in the Walt Disney Theater (where the One Man's Dream attraction is now), and the previews would change throughout the year as new movies came out. All-in-all it was around a full 2-hour show. I believe they changed it sometime around 1992-94, when the shows were split into two: the tram tour and the soundstage tour. They then changed it again to incorporate the water tank and the prop house into the tram tour, and making the soundstage corridor into its own attraction called Backstage Pass (which was closed most recently when I was there two weeks ago).
Hope that helps jog everyone's memory.