Approach
Sculptor's Idol (Mibu Village)
Give Unrefined Sake to Isshin Ashina
Mottled Purple Gourd (1800 sen)
Dragonspring Sake (1000)
2 Treasure Carp Scales (500 each)
All the way up the slope with the dogs.
Behnd one of the first couple of buildings.
First half
Everything up to Water Mill.
Pacifying Agent (entrance fence)
Inside the house right next to the fence, accessible through a hole in the roof.
Mibu Balloon of Wealth (boat)
Fistful of Ash (house)
Sakura tree
Pellet (trench)
Sculptor's Idol (Water Mill)
Give Dragonspring Sake to Emma
Mill house
Use the small shack to reach the roof, then cross it to reach some stilts and planks.
Hill
Across the pond
Pellet (boat)
From the thatch roof with the Pine Resin Ember, grapple up on the left side and follow the slope up to a gap you need to jump over.
Up the road
If you didn't send him to the Abandoned Dungeon.
Waterfall
Divine Grass (chest)
Priest's house
To enter, crawl under the house through a hole to the right of the entrance, and follow the path until there's a secret door above you that you can "hug".
At the door
"Gulp... Gulp... Gulp..."
Second floor, reachable by grappling from the backyard.
Sculptor's Idol (Wedding Cave Door)
Wedding Cave
Assuming you've already collected Mortal Blade and Lotus of the Palace, picking up the Shelter Stone will trigger mid-game changes. Make sure you've done everything missable.
With Shelter Stone and Mibu Breathing Technique acquired, you have started mid-game and can access all the underwater areas.