I saw on a beamdog forum post that somebody was extracting the game .are (area/map) files and getting zoomed out pictures of the entirety of the map and then placing the files into BG2 engine and running around with a bg2 character/engine.

Does anybody know what tools would allow you to extract and screencap entire map files? I've attached a screenshot from google of what the pictures looked like and I'm curious the tools needed to extract/view the maps in their entirety like this.

I'm afraid I don't know. The cluebook had maps, but I suspect they were simply screenshots of the map view, not full size maps.

They might have used this tool:
https://github.com/JohnGlassmyer/dsun_music