I grew up playing video games like Morrowind or Baldur's Gate where all the content is already there and all you do is go out there and interact with it, with all the limitations of having a computer DM (e.g. lack of actions having ingame consequences to the rest of the game world, rewarding roleplay, etc.)
Now when GM-ing a Pathfinder game, I feel like I want to provide that kind of sand-box exploration freedom, where the characters could at any time attempt to do anything they chose to. For example when running "We be Goblins" they chased a monster to it's lair and I made checks to see if they got lost, they didn't. But I really didn't have anything to give them if they had gotten lost. Since then I've looked at the maps of the Inner Sea regions, and the Brinestump Marsh and surrounding hinterlands of Sand-point. And it's been using up a lot of my free time, and reminding me that games like Morrowind took years to build, and even if someone already built it familiarizing myself with the world enough that I wouldn't slow down the game too much having to react to the players choice of unexpectedly say exploring the neighbor town rather than go to the prepared forest or stay in the current local, leaving me wonder if it can even be done at all.
Has anyone here attempted to run such a game? Successfully?
I'm not interested in such a game working hypothetically or in theory, only actual experience. Whether that be your own, or with reference (e.g. link to a blog) to someone who reported on actual experience with that.
There seem to be three ways to provide material anywhere you go, one being prepping all areas, the second being having a way to quickly generate content as needed (improv or randomized tables), and the third "playing in other people's sandboxes" is looking up pre-generated content as needed.
For the first I'm worried about the amount of work and the second I'm worried about having to document everything I generated, so they could return to that location later. And the third seems like it would be too slow to do during the session.
Someone linked a question asking what sandbox means, and there @RSConley mentions "many PC groups feel rudderless and the game feels without direction. In fact, if you read through various forums posts, such as on ENWorld, you see these campaigns fail more than succeed." Assuming that these games failed despite having made it past the content generation problem (rather than failed because of these) there seems to be a risk that this kind of play isn't for everyone.
Computer analogy: In Morrowind if you found a good weapon (which is in that spot no matter your level, if you can find a way to get it), or leveled up early, that could make large portions of the game far too easy - so you either end up doing way too easy things or missing content just because your ueber hero is above that kind of quest. Which makes the world make sense. -- In Oblivion the rest of the world levels up when you do, but spends their points more optimized for fighting than you do (cause monsters don't need charisma). Suddenly all robbers are wearing armor that is so expensive that they could sell it and live in wealth for a long time to come rather than attack a known hero. It makes the game mechanically better (i.e. challenging) but the ingame world illogical.
The first world has creature ratings only descriptively as reference (dungeoneering check says you should probably run, this thing is dangerous), while in the second the player's level changes the world around them (independently of their actions), as though CR is prescriptive. Same goes for wealth by level. In a simulationist world you have the money that you got a hold of, however even if you luck out, magic item stores only sell what they have. If you get too rich money is no longer a motivator (happened very early for me in Morrowind), at which point roleplay matters.
In the video game I did it for the out-of-character reason that I'm a completionist who wants to see all the content. What are your character's motives for adventuring? Start bettering the world for free? Donate loads? Or would he just buy a castle and retire? This kind of role play requires having actual motives for your character, thinking about things, rather than just chasing plot for the entertainment of seeing it. Players as consumers and plot as product might be the standard, but I can theoretically imagine for some groups of role-play enthusiasts (or people who love the exploring/freedom aspect of the game) this could work, but it seems really difficult to pull off.
Now what I'm asking is are there any success stories of it actually being done, rather than fantasized about? How did you/they do it?