|Main Street||Adjacent rooms||Mama Turtle Room|
As you come into this room from Main Street, you want to jump into the door transition. If you manage to jump on the last frame before the door, you can make it up to the middle ledge, where you can fire a Hero shot at the door to Mt. Everest, then walljump to the door, then off of the door frame.
If you walljump towards the door with the appropriate height, you might be able to align the door by hitting the transition farther to the left. This may require expanding your hitbox by breaking spin. However you will need to know the appropriate places to get the walljump for this, since if you didn't get enough height off of your walljump you may just barely miss the transition and fall down.
If you missed the jump into the door transition you can arrest your momentum to avoid bonking into the fish before walljumping up and doing the same strats as above.
If you jumped slightly too early you might be able to still keep your upward momentum by doing a turnaround as your head hits the overhang right after the door. This uses essentially the same mechanic that allows for a Quick Drop.
On your way to Tourian you can jump very early through this door transition, bonking against the ceiling before the door. This will allow for a better aligned door coming into this room, then you can Space Jump up. After the Hero shot, it's then much easier to Space Jump through the door to Mt. Everest while moving left, allowing that door to be aligned as well.