100 Coins in Rainbow Ride

From the start, Long Jump to the pole. Collect 2 coins from the Fly Guy and 5 coins on the lowest step (7 coins total).

On the first swinging platform, collect 5 coins in a vertical line.

At the far end with two sets of donut blocks, collect 2 coins on each set (4 coins total). Jump on donut blocks to keep them from falling.

Jump up the donut blocks, past the flamethrower, to the slope with tiny ledges. Stomp the Goomba for 1 coin.

On the next sloped platform, collect 5 coins on the donut blocks on either side.

Jump to the area with the pole, climb it, Long Jump back to the starting platform, and take the flying carpet. Collect 8 coins on the platform along the way.

You will reach four spinning platforms. A Lakitu will spawn 5 coins when defeated.

Collect 8 coins on each of the two sets on the spinning platforms (16 coins total).

Go to the maze area. Blow up the two Bob-Ombs for 2 coins.

Hit the Blue Coin Block at the far end of the maze. Collect the single Blue Coin against the wall and the remaining Blue Coins at the top of the maze (6 Blue Coins total). The despawn timer is short, so act quickly.

Collect all eight Red Coins within the maze.

Return to the spinning platforms and take the flying carpet that goes to the big house in the sky. Collect 2 coins on this carpet ride.

On the magic carpet ride to the house, collect 3 coins above the first set of donut blocks.

Collect 5 coins inside the house, 5 coins on the platform after the Amp, and 5 coins before entering the house the second time (15 coins total).

You will end up on the roof of the house. Slide down the front slope and hold forward to land on top of the maze if you need more coins.

Double back to the flying carpet and take the one that goes to the flying ship.

Upon reaching the flying ship, defeat the two Bob-Ombs and the Lakitu.

Collect 8 coins around the pole on the ship.

If more coins are needed, blast yourself to the platform with the Chuckya for 5 coins.