There isn’t much change between the episodes in Ricco Harbor, but for the 100 coins, you’re going to use Episode 3. At the beginning of the level, there are some crates next to you, so break them to get three coins (3). There is a ship that you can board to your right (the arrow sign will point to it), with another eight coins sitting on the catwalks above the boat (11). There is also a Blooper on the ship, which will yield a single coin for jumping on it (12) Return to the beginning of the level and enter the manhole now.
You will get three coins for going into the manhole, as well as six more for following the tunnel to the next manhole (21). Jump out of the second one for two more coins, then go right back in, taking the side paths and doing the same thing as before at each point you can “jump” out of the tunnels. For fully exploring the entire tunnel system, you will net yourself another 29 coins to the first batch (50). Double back to the beginning of the level and jump on the smokestack of the large ship right in front of you.
With the Hover Nozzle equipped, you should be able to Side Somersault and hover to reach the ledge above with two coins (52). Although it may take a few tries to get it, jump down to the crane moving back and forth by the large ship from before. There are a total of 12 more coins you can get by standing on the top of the crane and letting it carry you from one end to the other (64). Return to the smokestack and do the same maneuver as before (Side Somersault and hover) to get to the catwalks above the water.
There are a number of Bloopers up here, but the coins they drop will sometimes fall in the water, so don’t bother chasing them. For now, follow the catwalk straight ahead and collect the seven coins on the beam connected to the buildings along the wall (71). You’re going to need the Rocket Nozzle and if you didn’t unlock it for this level, you will get some coins along the way. Go back to where you first got onto the catwalks and look for the moving hook. Ride this hook to the other side and climb the cage over there, punching the door with the Y button. On the next mesh, jump off to the platform and jump over the gaps, collecting the seven coins in the one gap (78).
The Rocket Nozzle will be right past those coins, which will unlock the rest of the boxes in the level now. While in the same area, there will be four more coins a little further along the same catwalk (82). Back at the beginning of the level, there is a tower with some scaffolding around it. There will be two coins on one piece of scaffolding, as well as seven more coins in the air above the top of the tower (91). You might already have 100 coins, but if not, there are four coins underwater, underneath one of the platforms (95). In the air above the water over the one path for the Blooper race are more coins, but these likely require you to use the Rocket Nozzle and are annoying, since you only get one at a time (103). The Shine will spawn near the fruit-dispensing machines.