As far as removal, the whole dash comes out of my '55, so I'm sure a 57 is the same. When mine was out I'd already pulled the steering column, the seats, and everything else in the way, including the heater. I was redoing the whole interior, and rewording the whole car. So just what you have to pull to just get the dash out I'm not sure.
If the wiring is original, you're likely to find the insulation cracking, and one thing is going to lead to another. I'm not a resto guy, so I used a modern kit and wired the whole dash on the bench with multi connector plugs for the re-install.
My dash was pretty smooth, as it just had the simple vinyl cover that glued down. The 57 has more complicated curves, and I don't have a clue how much body work you might need for paint. The other thing you might consider is the resale value for a non stock dash. The 57 bird was a real step up for Ford, and the key change (including the gauges) from prior years