New Type of Map System...

[Obsidian]

Okay i just recently (in the last 4 hours or so), started working on a new type of map system. There is 1 horrendously large map, and tiles are loaded/destroyed as you move, so the entire game is just 1 map. I was going through it, and i got a lot of really good ideas on how to handle the different things things that are usually managed on a map-by-map basis (e.g., NPCs), my problem now though... is what do to do about "playerdata". Should i send it to everyone when they join the game? Should i not send it until they are only "x" amount of tiles away from someone else?

I've just been kinda stumped thinking up a logical, and processor/memory friendly way of making it all work. Any ideas from you guys would be great though