Now I'm deep in the meat of the last half of The Waste Lands. It checks in at 588 pages and fits in quite nicely with the previous book.
Turns out that I was correct, Roland is slowly going mad because of the paradox he created by saving Jake. Turns out that Jake, back in his world, is also going mad because he's living out the other end of the paradox -- he should have died, but he's alive.
Neeless to say the paradox will be resolved, sort of, and Jake will join Roland's merry band of gunslingers.
They'll also be attacked by a giant robot bear, travel through ancient ruins, and encounter artifacts far beyond the current technological abilities of Roland's world. I keep thinking of Atlantis as I read these passages, that Roland and his pals have discovered an ancient civilization.
But the roads must roll, and I must keep reading.