BerryMuffins posted... I got over to the castle and climbed up the ladder to the ropes. Then I guess I'm supposed to jump over the white board and onto the turret but I just keep falling off and getting nowhere near.
It doesn't help that I didn't kill that thing that shoots me all the time on the turret.
That 'board' is a sword blade.
Here's a video walkthrough of that area. The castle section starts at 3:18. The part you're having trouble with is at 6:30. The link should take you there.
Psychonauts - Part 51 - Waterloo World by Mahalo http://www.youtube.com/watch?v=CZvxT5ASFXM&t=6m30s
BerryMuffins posted... Thanks but I already looked at the video. I'm finding it impossible to balance on the sword.
Then try stretching your jump as far as possible. Delay the second jump of the double jump to the last split second for maximum distance. Try to hit the levitation balloon hang at the highest part of the jump.
Edit: Here's an alternate approache, courtesy of shakealmighty.