I have never removed the dash on the ST (or another Explorer) but through my job I have removed or had a hand in removing many. I wouldn't suggest it to someone who has little experience working on cars, but for someone with some experience it shouldn't be too bad. In most cars, the dash is typically only held with a few bolts. But then there are several other things like a bunch of wiring bundles, trim, brake booster, the heater core, etc that are all connected to the dash panel. The toughest parts are typically
Removing the steering column
Disconnecting and removing the heater core -- the lines passing through the firewall will need to be disconnected.
Draining and disconnecting the AC lines
Physically living the dash out of the vehicle -- you'll likely need help.
Do yourself a favor and remove the front seats to give you some room. It varies a little from car to car, but often the heater core and dash and steering column will all come out in one piece. This is a little unruly to lift out (hence needing help) but is often the easiest thing to do.
I'm sure there are people on the site here who have done this you can give you specific advice on the ST. It's not that hard, but it's kind of intimidating.
Hope that helps,
Rocks
