Locations

Peach's Castle: Has many rooms, your here at the very beginning of the game, and rarely need to go back here, has very few items.

Toad Village: You cannot go here until it's rebuilt eventually at some point in the game, has a ton of items.

Destroyed Toad Village: Here you must save any toads still alive, you go here pretty early into the game, has a bit of items.

Shroob Town: You can go here optionally and get some cool stuff but it's mostly pointless.

Mount Lunch: Has some very rare items and a few caves, you go here very early into the game.

Flower Fields: You go here very early into the game, doesn't have many items.

Swirling Hills: You go here a bit in the middle of the game, quite a small area, with some items.

Pillow Palace: You go here at basically the very end of the game, this place has a ton of items in some areas.

Tower of Telepathy: You go here much later into the game, has a few items.

Block Islands: A small place that you go to a few times in the game, has a lot of items.

Bowser Valley: A big area with a lot of items, you go here once, then you can go here optionally for other stuff.

Bowser's Castle: You go here much later on, then after that you can optionally return for a few extra items.

Frozen Lake: A small area with some items and an underwater section, you go here a little early into the game.

Puzzle Plains: A place with a cave, 3 houses, and tons of puzzles, you can get items and make progress here by solving the puzzles. You go here very early into the game, but can always go here optionally.

Dizzy Dungeon: A small optional area that gets you a few items.

Wariomares: There are many Wariomares to enter all the time, they are usually very small areas with some items and other stuff, very few are optional.

Test Rooms: Unused in the final game, there are 4 of them, all testing specific stuff.

Starman Mountain(unused): An unused area in the final game, has a bunch of items, and is quite big.