Decided to make a video showcasing all the places you can get regional maps. Will describe each starting point below:
Crateria: Starting at ship
Realistically you'd prob want to get after missiles and before bomb, but I figured the ship was an easier point to start from.
Brinstar: Bottom of Crateria to Green Brinstar main elevator
If you want the map, you can get it almost right away, which is cool.
Midfair: Bottom of Red Brinstar to Norfair elevator
Blocked by a power bomb door so this one takes a while. I usually sequence break and grab a different power bomb to avoid having to go back to Brinstar but yeah. This map room is also close to the entrance.
Wrecked Ship: Boss room
You need to beat the boss to unlock the map for this area.
Maridia: Top of Red Brinstar to Norfair elevator
Using the alternate entrance to Maridia, the map room is pretty close. Convenient for me bc I don't like the other entrance :p
Thanks for watching c: