My going thought was that you'd have a community with an individual post for every town and/or city, at least (and areas/caves/routes as well? IDK, that could get HUGE), and then have links to them on a stickied navigation post or in the userinfo (or both), and then use the comments of each post to let people submit blurbs for stuff they've added?

And then whoever was maintaining the posts could maybe link each comment in the post itself, in a fast directory of what's there so you could tell at a glance, rather than having to scroll through all the comments longhand.

Laid out like that, it'd be a ton of work to get it up and running, so I don't know if it'd be worth it. But that'd be how I would do it, at least, if I were undertaking it.