I've figured out how to answer most of the questions I've asked, if anyone can fill in those I'm still unsure of, it would be greatly appreciated.
How do I properly replace the existing airport within the P3D library with my new updated one?
IN WINDOWS EXPLORER:
- Go to C:\Program Files\Lockheed Martin\Prepar3D v4\Scenery
- Create a new folder called 'Addon Scenery'
- Go into it and create 2 new folders, 'scenery' and 'texture'
- Copy your .bgl file from where you saved it (in my case it's C:\MSFS\FS Design Tools\Airport Design Editor 175\P34\Projects)
- Paste it into the 'scenery' folder
IN P3D:
- Scenery > Add Area... > Browse > Choose C:\Program Files\Lockheed Martin\Prepar3D v4\Scenery\Addon Scenery
- 'Scenery are title:' field should automatically be filled in with 'Addon Scenery'
- In the list, the 'Addon Scenery' should be under 'Scenery Area' column as priority 1
- OK
Where do I put my bgl files?
- C:\Program Files\Lockheed Martin\Prepar3D v4\Scenery\Addon Scenery\scenery
- refer to above for more in depth steps
How to I automatically detect what location my new airport is in, and then go to it?
IN P3D:
LOCATION > Change Airport... > Type in ICAO ID or Airport name to narrow down options in the list
Is there a way to change the coordinates input from DMS to DD?
Unknown
Try to avoid doing this as this will result in problems such as plane not aligning with runway properly, being partially submerged in the ground, crashing on startup, etc.
How do I navigate the airport runways without necessarily knowing how to fly the plane?
Y - Turn on Slew Mode, red text will appear at Top Left Corner
Optional: F11 to see 3PV or plane
F3 - increase speed to go higher
F4 - increase speed to go higher FASTER
F1 - increase speed to go lower till you hit the ground
F2 - STOP HEIGHT
Disable Numpad to navigate, make sure Pause is off
8 - increase speed forward
2 - increase speed backward
4 - increase speed left
6 - increase speed right
5 - STOP MOVING ALL
7 - increase dip speed left
9 - increase dip speed right
1 - increase rotate speed left
3 - increase rotate speed right
Additionally, this video might help with slew mode navigation: