His later stuff feels much more planned, in that it kind of all ties into his big meta-project of the Dark Tower, even the early stand-alone stuff, that he more or less retcons into that universe.
[1] http://stephenking.com/xf/index.php?threads/king-forgets-cuj...
There is a famous (mostly misattributed) quote to that effect: http://www.goodreads.com/quotes/84190-sometimes-i-write-drun...
Though Hemingway didn't say that, he was definitely a merciless editor of his own work. I dropped in on this (http://www.themorgan.org/exhibitions/ernest-hemingway) exhibit recently that had early drafts of some of his most famous stories and books and it was remarkable how many whole pages and chapters he chopped out just prior to publication.