Good review. The book is so full of interesting characters and incidents that it's easy to forget something like the Alzheimer piece (which I did; it was only when you gave the Michael Caine and Kirsty McColl song references that I dredged up the book.) I've only read The World According to Garp of his other books and can't actually remember much about it - certainly not as much as Cider House.
Tobey Maguire, who played the other main lead in the film version, of course went on to great fame as Spiderman. Caine, I thought was pretty good and captured the role of the doctor in a so-so adaptation.