Dash removal is fairly straightforward:
Carefully pull off the bezel around the stereo & A/C controls, remove visible screws. Remove both knee/kick panels, then remove the visible screws across the bottom of the dash; don't forget the ones in the door jambs. On the Gen 1 cars, you have to push the button on top of the headlight switch (easy to reach once the knee panel is off) to release the shaft and knob from the switch assembly; on the Gen II's with the rotary switch, you press a paper clip or other straight wire into the hole on the bottom of the external knob to release the knob from the shaft.
The top edge of the dash is secured with push-in snaps, so you have to use some sort of non-marring tool, such as wooden popsicle stick (or screwdriver with tape around it) - once you get it started, you can carefull pull the rest of the snaps loose without the tool.
The hard part, once the dash is loose, is getting it out past the steering wheel - it takes a few minutes of careful jockying (with the wheel tilted all the way down).
Once the dash if off, the gauges are all easy to get to, and each is secure by a couple of bolts/screws that are on the surface/trivial to get to.
I'm doing this from memory, its been a couple of months since I've had my Gen II dash off, and a couple of years since removing my old car's Gen I dash - forgive me if I forgot something. However, this should be most of it, and the rest should be easy to figure out.