Actually, because of this topic, I decided to download a copy of the hack to check it out, so I think I can help you. Choco 4 short answer: just past the halfway mark there's a pipe sticking out of a hillside. That's where you need to go. Choco ghost short answer: after the first door, use the springboard on the platform after the first set of stairs (right side of the screen, right above the four ghosts guarding a question block), take that door and head to the right.
More detailed answers: Choco 4: just past the halfway mark there's a P switch. Don't hit it, but carry it to the pipe in the hillside (our eventual goal) and leave it there. Continue to the right and you'll get to a "valley' with a tip box and a question block. The question block is a string of coins and the trick is to get the coins out of the valley heading to the left, then going underneath the pipe. The key to lining things up is to have the coins skim the top of the platforms just to the right of the pipe. Once the coins are set up, hit the P switch, run into the pipe and the rest is straight forward.
Choco ghost is similar and let's see if I can explain it clearly. First off, you may want a feather because flying is easier than using the block boos: waiting for them, hoping they form usuable stepping stones, etc. What I recommend again, is to set up the string of coins, then hit the P switch. So, head through the first door, no big deal. Second platform on the right, there's the door we want. A big boo is "guarding" it, but shouldn't be much of an issue. We now find ourselves at the top of a room. Head to the right a bit and you'll find a question block. This is our string of coins. If you jump/float further to the right, you'll see a wall. The top of the wall has plenty of room for Mario and a little ways down, there's a narrow gap. Our goal is to get the string of coins into that gap. And while we can't see the gap from the platform with the question block, our hack creator did give us a visual guide to aim with. Standing on the platform with the question block, you'll notice two lamps. Those lamps are positioned at the same height as the gap. So, let your string of coins go through the gap. The P switch is at the bottom of this room, at the base of the wall with the gap. Carry it back up to the top of the room, hit it, run to the right and you're done.