After you defeat Punchinello, you help Dyna escape the mines on a mine cart.
About the Mine Cart Ride
During the mine cart ride, you can press A or Y to brake, press the jump button to jump, and press X to spend a mushroom to accelerate (if you have collected any mushrooms). There will be times that you need to brake to avoid falling off of the track, especially if you are about to turn and are going too quickly. You can press Start at any time to pause the game.
The mushrooms are only used for acceleration. Only eight are displayed on screen, but they don't disappear if you collect more than eight; the others just aren't displayed. If you want to get the fastest time, be sure to use your mushrooms. You don't get to keep them after the mine cart ride.
You won't get any prizes for this ride, but if you want to make it easier to get prizes later, be sure to go as slowly as possible this time.
First Top-Down Area
There is a mushroom straight ahead. You have to jump to collect it.
At the first split, go to the right to get a mushroom. After that, go to the right and there will be another mushroom.
There will be a long straight section of track, and you will need to brake (press A or Y) to avoid falling off of the track at the first curve and the second (hairpin) curve.
Then, at the next split, go to the right to get a couple of mushrooms.
At the next split, go right again to get another mushroom.
There is another hairpin turn, so be sure to brake.
There are a couple of mushrooms up ahead, including one that is over a broken section of track. Be sure to jump to avoid the broken track.
After the long straight section of track, there will be a left turn, followed by another left turn. Be sure to brake before the second left turn.
After you reach the end of this section, your time will flash on the screen.
First Side-Scrolling Area
Jump to the higher tracks to get five coins, then drop down to get a mushroom, and immediately after that, jump to the higher tracks to get two more mushrooms.
From the track where you got the two mushrooms, you will drop down to the track below. Before you fall off of this section of track, press X to accelerate, then jump, and you will get the mushroom, then you will land on the lower track and get nine coins. If you don't accelerate, you can instead jump onto the track above the coins, then jump up onto the next track to get a mushroom, but you will miss out on the nine coins.
Up ahead, jump onto the higher track and jump to get another mushroom. To the right of that, stay on the higher tracks to get five coins (jump the two gaps after those coins) and several mushrooms if you stay on the higher tracks. If you fall down to the lower track you can only get three coins, but you still can get several mushrooms if you keep jumping to higher tracks. If you are on the middle-level track with a mushroom followed by a gap, be sure to accelerate before you fall off of the second section, then jump to reach a high track to the right, then jump as soon as you land on the lower track to reach a high track with two mushrooms.
Second Top-Down Area
After that, you reach another top-down area. Jump over the gap in the track, jump to get the mushroom, brake at the hairpin turn, then at the next split, go left to get a mushroom.
There is a long section of straight track where you can accelerate if you wish. Be sure to brake before the curve. At the next split, you can go left to get two mushrooms, but it takes longer to go through this area because you need to brake at every hairpin turn. If you didn't go left, you can go straight at the next split to get another mushroom. Be sure to brake after that mushroom so you don't fall off at the right turn.
At the next split, you can go left and jump over the gap to take a shortcut, or you can go straight to get a mushroom, but it takes longer. If you went straight, be sure to brake before each curve.
From then on, the path is straightforward, but once again, be careful to avoid th gap in the track along the way, and hit the brake at every hairpin turn. This leads you to another side-scrolling area.
Second Side-Scrolling Area
The track in this area curves up and down. At the top of the first three curves, accelerate, then when you are about almost at the bottom of the curve, jump to reach the coins and mushrooms above each dip in the track. After you get the mushroom above the third dip, jump to get the three coins. Don't accelerate after that, because the coins and mushrooms are farther down.
At that point, don't jump, and you will get the last mushroom on the track. Then the mine cart ride will end, and there will be a cutscene. Afterward, go outside and there will be another cutscene.
To the left, there is a mole behind the counter who will sell you a Shiny Stone in exchange for Fireworks. The Shiny Stone is an optional item lets you battle an optional boss later. To get Fireworks, go into the house to the left, and talk to the mole in the rightmost corner of the house. You can buy the Fireworks for 500 coins. If you don't have enough, just remember to come back later.
Be sure to go into the item shop, where there is a new mushroom person behind the counter. You can buy a Lucky Jewel from this person for 100 coins. This item can only be used a limited number of times, and when used in battle before all enemies are gone, it gives you the "Lucky!" status, which lets you play the Yoshi egg minigame after the battle to double either coins or experience.
If you want to do the mine cart ride again, you can jump to the top of Moleville Mountain and talk to the mole. If you pay 10 coins, the ride is just for fun, but if you pay 30 coins, you will get 50 coins if you beat your high score.
When you're ready to move on, leave town and you can go to Booster Pass.