hawkeyefan
Legend
I think I need to add some context. The player will be exploring recently discovered continent. This continent will be the post-cataclysm ruined version of said setting. Therefore I prefer a setting the players know nothing about.
Ah, okay.....so you really are just looking for a setting that has material you can use, rather then using the setting as a starting point for the post-cataclysm game?
In that case, Forgotten Realms may be too large and have too many different iterations for what you want. What about Greyhawk or Mystara? Both have plenty of source books, but not nearly as much as FR.
When I was playing Pathfinder, I found the Inner Sea World Guide to be a great sourcebook for the Golarion setting. It's definitely a vast area, with all kinds of different sub-settings as countries/regions with their own vibe. You could use that and go with either the entire area, or just pull out a region and limit things to that. There are many more sourcebooks for the setting of Golarion that go into much more detail on specific spots, but with just the Inner Sea World Guide you'd have plenty of detail to get started.