[0875FAC4 + AreaID * 4] + DoorID * 3C

List of pointers at 0875FAC4:0AD4 14AC 1E84 2BE0 339C 384C 3D74
00 Brinstar	08340AD4, 42 rooms
01 Kraid	083414AC, 42 rooms
02 Norfair	08341E84, 57 rooms
03 Ridley	08342BE0, 33 rooms
04 Tourian	0834339C, 20 rooms
05 Crateria	0834384C, 22 rooms
06 Chozodia	08343D74, 112 rooms

These point to all the room headers in the area, each entry is 3C bytes

00: Tileset
01: Foreground compression
02: Level compression
03: Back-level compression
04: Background compression
08: Pointer to VRAM foreground
0C: Pointer to level
10: Pointer to back-level
14: Pointer to clipdata
18: Pointer to WRAM foreground?
1C: Bg3 Scrolling?
1D: Transparency level
20: Default pointer to room's enemy data
24: Default spriteset
25: First spriteset change event
28: First pointer to room's enemy data
2C: First spriteset
2D: Second spriteset change event
30: Second spriteset pointer
34: Second pointer to room's enemy data
35: Map X coordinate
36: Map Y coordinate
37: Effect
38: Effect Y position
3A: Music track