Yes there are 10^157 possibilities but I suspect it's not a factorial process to solve it - let's pick a random page, we compare it with the 99 others and find the one that follows it and the one that precedes it (198 tests) - now we have a chunk of 3 lets do the same again (194 tests) now we have a chunk of 5 (190 tests)
The result is more like 2*(99+98+97+....+1) tests which is ~10,000 tests something a person can do in a real amount of time - nothing like a 10^157 age of the universe sort of thing.
(of course there are going to be some pages that might have multiple potential subsequent pages - sentences that scan and make sense - so as there's more of a puzzle in there)
While some of the pages end in a poem fragment that can be plausibly matched to a poem fragment at the beginning of another page, none of the pages have obvious continuations to other pages. Each page starts at a whole sentence and ends at a whole sentence, and I haven't spotted any obvious hints, like dialogue spanning more than a page.
At the moment my plan is to cut the book up, glue a lightweight magnet to each one, get a couple of large magnetic whiteboards, and just stare at and rearrange them every now and again for the rest of my life.
Since people have apparently submitted attempts that were incorrect, it seems likely that it’s not at all easy to verify whether any pair of pages is correct.
I doubt it, considering people have apparently submitted attempts which were unsuccessful. Assuming at least some of those were from fairly serious puzzle fans giving it a serious attempt, it’s probably not a puzzle where the solution is easily verifiable.
Well mostly I guess that the first part has to do with checking that the end of one page matches the beginning of the next, and makes sense (the "makes sense" bit probably can't be brute forced) - 100! is probably not easily brute forceable either - but I suspect that this is really a process something that might not actually be strictly factorial in nature.
But once you've done that I think there's an actual mystery to solve as well - probably something that requires an actual human to read it