I used CAW to create a slightly modified version of a custom world, using the second method from here. However, the edited version does not seem to work with Traveler - when I try to send my Sims there, they just disappear on arrival and I'm thrown onto the Edit Town screen, like I was traveling with an empty party. The original world works fine. Any ideas what I need to do differently to get it to work?

I suspect it has something to do with the new resource identifying the global layer that Traveler didn't like. I recommend not using the UNKN 0x0498DA7E resource provided in the second method. Create a new CAW project using only the 0x0477BD6A file, redo your changes and see if it works after that.