Interlude: On Running the Sandbox

I don't usually like to interrupt the narrative, but Eli asked me about how I run the world that is Beyond the Wall. There are a ton of sites out there with probably better advice than I, about running OD&D games, but here goes:
Despite the fact that some of my best games have been run totally on the fly, ad libbing as I go (the kobold village was completely done, then I left it at work and had to make the whole thing up), preparation is key. Have your world ready, and then it's a matter of the PCs just going there. If they decide to left to the old tower, the tower's done. If they go right on the road, the old marsh is already stocked. Throw in random encounters (Logun was just rolled up, but instead of a werewolf just attacking the party, I had him appear in human guise, and halfway helpful).
I started with an idea, which BTW isn't really that original, of a world for the most part civilized, but beyond a certain point, the world was still wild and untamed. A little of the wild west mixed with Hadrian's wall. I've run a still floating-in-the-aether narrative campaign. It's completely frozen because too many members have a hard time meeting at the same time. The story is too ingrained in the membership to just drop one out. This began my interest in the sandbox. I wanted anyone to be able to play whenever. My kids want a quick session? Done. This website was set up, mostly as a way for those that might have missed a session to still keep up with what's been explored, who's doing what, etc. Players can come and go to the world as they please.
In my mind, too much time can be wasted screwing around in town, talking to PCs. For my games, Wall is where the adventure stops and ends. The world of Wall is there, the blog and descriptions from me are there so the PCS have place in their minds, but interaction is limited, unless it has to do with a adventure hook.
To wit, RUMORS. Both on the blog and in the Hole are rumors. These are story hooks to get the characters out Beyond the Wall. They can use them or not. The Well of Souls was just a rumor. The PCs had no idea where it was, til they found a map dropped by a bandit. Again, they could have just not gone there and ignored the map. You have to be prepared for that.
Back to the idea of Wall for a moment. I started with a rough map. I put it on the cover of my spiral notebook. It's 8 squares by squares. I decided each square was a hard days ride in good weather to cross. No scale. PCs don't know miles, they just know the narrative. "A day has passed, it's noon", etc. The squares are numbered A-1, A-2....I blew up each square and made a hex map 8 hexes by 8 hexes. Each takes about an hour to cross. This works for two reasons. 1-You check for encounters every hour, so each hex. 2- Helps me keep tract of time. And it's not so big an area you'll miss something
 If you think about the traditional D&D sense of each hex size. Go walk into some local woods by your house. Even a in a small forest, you could walk for hours, but still walk right past the goblin encampment.
In each of these hex maps I've got 4-5 places of interest spread across it.. Normally I just make a little picture of a tree or a castle, then come up with some menacing name to match. These get put in the notebook. Then I start writing the info about each. Some are just quick little scenarios, some are huge modules in themselves. These get put in the notebook behind the relevant page. Now, repeat.
The area immediately outside wall are 1st level, then I fan out from there getting increasingly harder. So the farther they go, the harder it gets. There are pockets within that are harder, and some easier. Ol Nik, is a heavy creature in what is mostly a 1st level area. I use stuff from wherever I can find it. The current dungeon I found online, but tweaked to fit.
I by no means have the whole world  done either. I have what I think the characters will explore in the immediate future done, but that's it. Hidden within all these random events/encounters is, I have to say, an overarching story that is slowly unfolding. The characters have little snippits here and there, but not the whole story.
Now, as far as DMing it goes I have some rules.
-Don't railroad. Part of having a complete world, is for them to explore, or not.
-Allow the dice to decide. Some of my best stories have sprung from random rolls. I also usually give everyone a second chance, but that's it. Dimzad was played by a somewhat reckless youth, and eventually he paid for it. His sacrifice allowed everybody to realize, they were mortal. That one death in the party has transformed how everyone plays now.
-Don't over think it. This ain't Lord of the Rings. It supposed to be fun, not homework.
-Embrace your inner 12-year-old. What would you like to have done/seen/fought.
Since I started it, it has been a blast. Our group ranges from 9 to way, way older than 9.
I rambled a bit, but hope that helped. I don't want to turn this into a blog about DMing styles, but if have a question you throw it my way.
I'm toying with the idea of letting others outside my group run around but haven't found a convenient to do it.