Thinking about this over and over, I believe the door in Crawler's Nest (S) was a missed opportunity. Other places in Vana'Diel can have these doors to prevent access to Apex Camps and Key Items would be required to access them.
Place an NPC in each major region to purchase a Key Item.
NPC would only let you purchase a Key Item for that region if you have the following things done:
-All Missions from Nations, Rise of Zilart, Chains of Promathia, Treasures of Aht Urhgan, Wings of the Goddess, Seekers of Audolin, & Rhapsodies of Vana'diel. The in-game check would be to see if the RoE is completed.
-Battlefields Unafraid of the Dark, Black and White, Sealed Fate & Heroines' Combat II are completed. In-game would be a title check like most quests.
-The Key Item would cost players 500,000 Conquest Points for Apex camp access in the Mainlands(FFXI, RoZ, & CoP). 500,000 Imperial Standing for Apex camp access in areas connected to Treasures of Aht Urhgan. 500,000 Allied Notes for Apex camp access in areas connected to Wings of the Goddess. Lastly 500,000 Balyd for Apex camp access in areas connected to Seekers of Audolin.
Even as a veteran player, I do not have the requirements for access to those Apex camps I suggested, yet. If a Game Master or STF does a check on players at those camps, they should be able to easily tell if they really have access, or if they used a third-party program to get there.
Thank you for listening.