I don't remember the old track part of FitH, but I do remember when the bridge used to collapse...
Hmmm... Random trivia... Well, if you go on the Marvel Cave tour either before Memorial Day or on a day when the waterfall room is flooded, you'll be taken along the upper trail, and that's where you can see the reproduction of the Lynches' cabin that was used by Harold Bell Wright when he was writing Shepherd of the Hills (which, BTW, is 100 years old this year; I myself have got a first edition copy that my dad got me last year for my b-day).
Ummmm... Well, the petting zoo used to be over in Tom Sawyer's Landing near Becky's Carousel.
SDC used to give out silver dollars as change as a way of promoting the park when they first named it "Silver Dollar City".
The Main Street Square where the Gazebo Stage is now used to be the parking lot for the park.
A piece of info from Conductor Sam is that when Citizens reach a certain anniversary of working at the park (I think it's 25 years), it is commemorated by making a sign that uses their name that is then put up somewhere in the park. Terry Sanders has his hanging up next to the little waterfall at Mary's Springhouse; it says "Elect Terry Wayne Sanders for Stone County Judge"... it also says "Birdie Tweedle, Campaign Manager". Birdie Tweedle is the name of the Deputy character that Terry plays at SDC.
That's all I can think of off the top of my head at the moment.
~ "Becky" Joy ~