The dash really isn't in the way of too much. Unless you are going to be working on the bottom of the windshield cowl, it may not be worth all the trouble.
But if you do it, mine took a few hours to pull out, so you shouldn't have any problem doing it in a weekend. If you are going all the way, the heater will be pulled off the firewall, so your vent control cable, fan wires and defroster ducts will already be disconnected.
The wiring harnesses are your best place to start. You should have disconnects for each harness in the engine bay (at least mine did). Make sure you do and that you can pull them through the firewall. Remember the windshield wiper wires. I forgot those untill I started pulling the dash.
Mine is a column shift and the shift lever was screwed up, so I had to pull the steering column, but you should be able to just pull the shift lever and the steering wheel. If you're floor shift then it's no problem.
The speedo and the heater valve control are easy. There is a support screw in the center of the dash. Mine had a broken u-clip holding it in and that was a bugger to get to. Hopefully your po didn't hate threads as much as mine did. That's everything I can think of...
