New York Street first opened to traffic on August 1st 1989; it closed again after peak season but reopend full time in late 1990. Mickey Avenue was opened in late 1989/early 1990. Prior to that the backstage tour (which as you found used to depart from where the animation entrance is today) was a full 2 hour attraction with no escape. Once you borded the tram you didn`t get back into the park until the 2 part tour was over.
Part of the tram tour took in New York Street and the town square - with no foot traffic it looked a lot more realistic and like a `movie set` - and in 1990 a D ick Tracey `hold up` was performed for tram guests on what is now the San Fransisco street. This was way before the backlot theatre was built, infact that land and all around it was designated for Muppet Studios.
Also notable was the original `Walt Disney Theatre` which was converted into `Here Come the Muppets` for May 25th 1990. This is the space now occupied by `Voyage of the Little Mermaid` but when the park opened it was a theatre as part of the backstage tour, showing upcoming movie trailers and acted as the tour finale.
Opening NYS and Mickey Av to foot traffic and adding HCTM was a short term, almost knee jerk, reaction, to coping with the parks small size and overwhelming popularity. Park hours were extended to 11pm and then midnight, but the parking lot was still closed regularly by mid morning. This was extended too.
A catch 22 situation was created when Sorcery in the Sky opened. DMGM first held a fireworks show on August 12th 1989, though it was then un-named; the show was added to, Mickey was installed and it was first performed with a name on May 29th 1990. The show was added to round off the day and to give extra entertainment to a park that had just one small theatre stage - the original Theatre of the Stars which closed May 3rd 1993 to make room for Sunset. SITS kept guests in the park longer, but also meant the tram tour was closed, and as the park expanded so was Mickey Avenue, the plaza infront of Animation and also the area around Muppet*Vision 3D and New York Street for safety since a large part of the shows pyro was launched from the rooftops of TGMR and the tour post production building. Basically, the park was open but the only thing to do was shop or watch the show from HollyWood Blvd or Lakeside Circle. This of course got very crowded, and only Sunsets opening in 1994 gave some breathing space before the regular show was replaced by Fantasmic!
