Nope. Not much there besides adventure material. About 75% of the "support" can be found in the free download.
Only a couple of new magic items that are suitable for other use. Ditto for monsters. You could probably adapt the others, but it still isn't worthwhile.
If you're running in the Realms, in that particular region, there's probably enough info to make it a consideration, but that's a pretty significant corner case and still a very dubious return.
That's definitely one of those books that I wouldn't purchase unless I had every intention of making full use of it. GURPS world books are frequently purchased by players of other systems, even some who hate GURPS, simply because they have a reputation of being very well researched and written and have little crunch. These books, on the other hand, are focused fairly tightly on the railroad and not so much on the scenery, and that makes them pretty useless unless you plan to run the actual adventure. I was lent a copy of
Hoard of the Dragon Queen to run last season, but I have no interest in actually owning a copy since I'll never run it again.
No. Published dungeon crawls aren't worth my time to read--my sandbox diverges too much from the base assumptions. Easier to just invent stuff.
There is that, too. For my very first campaign (GURPS) a decade ago I did hours of prep, trying to guess everything the players might do and account for it. When game time came they ignored 90% of what I prepared and forced me to improvise most of the session. Since then the only prep I've done is pre-creating monsters and coming up with a couple of very vague outlines of evil plots they could get entangled with. The rest I make up during the session. On both sides of the screen I find modules frustrating and actively encouraged my Encounters players to diverge from it if so inclined.
The only exception is my steam-punkified
Warehouse 13/
23-inspired GURPS campaign. For it PCs are sent out on specific recovery missions and that has so far enabled us to have adventures that could have actually taken place in the real world (less so now that I'm adding more steam stuff and thus diverging from history). Since part of the PCs' job is to suppress knowledge of artifacts, only the few people affected by each one are aware of it, so the events surrounding them are forgotten by everyone outside of the Warehouse, meaning they may have really happened but no one remembers them. That may be my favorite campaign ever, probably in part
because of the total lack of combat. I actually have some suitable pre-gens and my research around one of the previously-recovered artifacts on hand in case anyone ever wants a GURPS demo.