The pad bit would be pretty easy. The pad would be a textured pressure plate with a script block underneath.
Also, speed and low gravity can be done in zones.
Good luck with it!
I had a go at doing this script, however there are a few things that I don't quite understand.[stage]
does the stage number go here? Should this be the name of the script so it knows which stage you're on? [=]
is it just the equals sign that goes here? 
what does this represent?
From what I understand, I have to set this as event driven script 'player dies' but I tried making the script exactly as you did but it told me that there was a possible undeclared variable. How exactly do I get this script to work, and teleport players to that stage that they reached when they die?