Overworlds have a certain set of expectations for them and a general shortage of tiles for gating (at least in EZGBZ), for instance, keys and shutters don't always make a ton of sense in the overworld. Blocking off paths tends to be limited to primarily trees and mountains, especially in making the screen layout organic-looking.
I'd just like to feel around for some ideas of how to address these limitations. I want my overworld to progress like a dungeon (or more acurately, a metroidvania) but still feel open in some sense, just like an overworld would.
I remember Link's Birthday using keys as entrances to dungeons, but I don't remember much more than that. Example quests would be appreciated, with video or cheats if possible. I don't exactly want to play through a whole quest to see how others have solved the problem.