Having Yoshi really helps here, because you can grab the blue Koopa on the other side of the rope barrier and fly up to the top relatively easily. When you get there, well, go back down on the other side. Go into the pipe at the bottom. Or, if you got the P-Switch on the other side of the barrier, you can use that and go in the pipe that's about halfway up the level. Anyway, when you go through either of the pipes, stomp the grey P-Switch and one of the blue P-Switches. Carry the other blue one to the end of the question block platform for backup. Hit the Amazing Flyin' Hammer Brother and use his platform to get to the next piece of solid ground. Or, you can get there a lot faster if you have a cape and just run to the other end of the block platform. After a little more, you'll reach the goal.
I fear the monkey in your soul.