I tore through this book... Some of that is do to it's shorter length relative to all of the (later) Dark Tower books, but it was also a pretty engaging story that moved quickly.

Of all of the books in the series which I've read, this one felt like an episode more than a self-contained story. While, in the strictest terms the ending somewhat resolved the main plot, it also held the aftermath away from us. King seems to have acknowledged this in-text with several meta references to the cliffhanger "Blaine the Pain" ending of book 3. But there was very little lag time between the publishing of this book and the 'final' book in the series, so I don't think it's as frustrating this time around.

I'm looking forward to reading Book 7 and seeing how this train pulls into the station after decades of work.