i can not for the life of me find a way past the quicksand part. it seems like no matter what i do i cant get past the last quicksand. any help will be greatly appreciated.

Go to the edge of the quicksand and as you start to go across have your camera angle slanted upward (if it's down you'll sink). Keep holding the walk button down and go across. Make sure that when you get ready to cross your at the shortest distance spot to cross. In some places you walk across the stone wall but mostly you just have to cross at the shortest distance spot with the camera angle elevated up some.