Any Dwemer Dungeon, but you will likely have to visit multiples to get just one. If I recall correctly there may also be a timer on how many you can aquire within a 24 hour period (?)
Not really. However there seems to be a timer on container respawns, even if you go to a new Ruin. I think it is something like 30 minutes, but maybe it's only 20. But I have gone to different ruins in quick succession and the containers are all but empty in the subsequent ones.
Also, once you find one chapter in the ruin, that's all your going to find. I have found chapters as soon as I walk in, or even before, and that's it for the Ruin.
Enjoy the game, life is what you really want to be worried about.