Get Teleportation Lv15.
Fully explore Sanctuary (you only need to do it once, all your other chars will forever benefit from it).
Fully explore 2nd Demon Prison (although you can 100% it without this) and Teleportation your way to the room with the Collection: 2nd Demon Prison box. Shared by your account and you will forever thank yourself.
Teleportation your way into the Aging Room in Shaton Reservoir (unless there’s a valid tunnel to it now), just for OCD purposes. Again, you can 100% this even without going into that portion of the map. Just nice to have all the darkness removed.
Did I miss anything? (Royal Mauso 4F no longer needs this)
EDIT: I removed most of my replies below and instead please see the following:
Lv200 DG - Fedimian Suburbs: (take note Zoomy is not required, I just accidentally zoomed out here) thanks to @reversen for reminding me 
Shaton Reservoir (for OCD purpose only)
2nd Demon Prison (for Collection only) - I suggest you go mouse mode and click on the [portal structure - upper left corner of screenie], your character will aim for that.
Sanctuary, needs video for easy replication (mouse mode needed to aim for a small corner of the screen):
Click there and your char should start walking towards the door by itself!
