Vault 87 is located in the central far western edge of the Wasteland. It is several hundred metres NNW of Little Lamplight and about the same distance SSW from Broadcast Tower KT8.
Basically, from the middle of the map all the way out to the west end.
There are 7 vaults as follows: Vault 87 Vault 92 Vault 101 Vault 106 Vault 108 and Vault 112
bak to where you got them except for dogmeat he at vault 101
The GECK is located inside Vault 87, North of Little Lamplight, it's only access point. http://fallout.wikia.com/wiki/Finding_the_Garden_of_Eden
I think it is in the vault where you find the violin, Vault 87 There is also some sheet music in Springvale School in the music room.
The Charisma Bobblehead is located in Vault 108, in the cloning lab.
There is many hidden quests in Fallout 3 but i there is one when you reenter the vault. (after you father dies) hang around the vault entrance.
vault 77 doesn't exist in the game.
you have to go through little lamp light & enter vault 87 though an auxilury exit u have to save 3 kids from Paradise falls to get in though and u have to sound the fire alarm in vault 87 to free Fawkes who u follow till he gets it for u
The real purpose of vaults was experiments. Most of all vaults had a secret experiments Vault 101 was designed to see how the residents react t long term isolation from the outside. Vault 87 was testing the effects of FEV virus. You can go to the fallout 3 wiki for more information.
SPOILER: no he is in vault 112 in smith Casey garage
You find him after completing "Tranquility Lane" in Vault 87. The vault is hidden in "Smith Casey's Garage" somewhere to the west. Just continue on the main story quest and you'll get there eventually.
Just North from Vault 101.