dash pad

Different methods for different folks for sure. Taking the seat out is not part of my my method.
Studs welded on the back of the dash cap have nuts on them. Each turned down end has a hex hd sheet metal screw, so yes the inst' panel glove box, etc.. will need to come out. I can sit in the seat to do most of this.
The only parts underneath that you will need to access are steering column bolts. Those and the speedometer cable can be reached while kneeling at the driver door opening.
Please take note of these common mistakes and ways to avoid them....
The service manuals and others will state tip the inst' panel over to access its harness connectors. They don't say how far forward to move before tipping.
The left circuit board on a rally panel has a very weak contact pin too close to the top edge.Very easily bent or broken. While kneeling at the drivers door , if you'll reach under the car and feel around a bit you'll find the speedometer cable held by a sheet metal strap. Set the cable out of that strap. Later on when the inst' panel ready to move forward, find the speedometer cable coming through the firewall and pull a little inside while pushing toward the panel. That should push the panel out plenty far enough to disconnect that cable and electrical connections. ( for what its worth, I'll separate the bulkhead connections under the hood and push that connector inside the cabin. That gives me ample slack in the wiring. Yes I'm slower and more methodical that most.)
Those who work under the dash while laying in the floor tend to use the steering wheel for a pull up. They aren't aware of the pizzy little bearing centering the steering shaft in the column. Pulling the column left and right and lengthwise while it is unbolted can damage all sorts of small parts or at minimum change their alignment inside that column. Take the bolts out, gently lower the column straight down to the seat only as long as necessary then go straight back up with it and loosely hang it with a couple of nuts.