04. Mushroom Kingdom
Outside
Head to the far right of the map and enter the item shop (the building with the spinning mushrooms over the door).
Item Shop
Head right and go down the stairs to the basement.
Jump on top of the old lady's head, then jump again to find a hidden chest with a flower.
Head back upstairs and talk to the shop keeper.
SHOPPING (do all of this within the shop menu to save time):
SELL:
Flower Jar
BUY:
Honey Syrup x 6
Pick Me Up x 7
Able Juice x 2
Shirt
Pants
Jump Shoes
EQUIP Mario:
Hammer
Shirt
Jump Shoes
Leave the item shop, head north and enter the castle, and get ready to react quickly.
SAFETY STRATS: You can save at the inn before entering the castle in case you mess up the next part.
Castle
As soon as Toad is finished talking, he will start walking towards the throne room. You need to immediately jump up-right and land on top of his head while he is walking. You have enough time to make a couple attempts at this before he reaches the door.
TIP: If you jump too far, you can actually land in front of him and block him from walking forward. If you get in this situation, it's an easy setup to jump on his head by jumping up-right without holding the run button. He should walk faster than you jump and end up directly underneath you.
Once you get on his head, wait until he gets to the door and pauses to open it, then jump off his head to land on top of the doorway in what appears to be a quasi out of bounds area. Jump directly up to find a hidden chest with a frog coin, the only opportunity that you have to grab it being right now.
If you miss grabbing the frog coin and saved at the inn, you can simply reset and try again. If you didn't save at the inn, you can continue the run! There is an extra frog coin on the Midas River course that can be used as a backup if you miss this one.
Proceed to the throne room and mash through the cutscene with the chancellor, then leave the castle the way you came.
Outside Again
Do the cutscene with Mallow and Croco, then run down and talk to Mallow as quickly as possible. Pick the first option so he joins your party immediately.
Now leave the Mushroom Kingdom by heading to the southeast exit and head to Bandit's Way.