The G.E.C.K

The way to the G.E.C.K. Can be pretty straightforward (Though there are Super Mutants constantly in the way) and the G.E.C.K. Is near the end. Your best bet to get it is to free Fawkes from his living quarters. There are two ways to do this, the first way requires you to have a science skill of 75. Hack the terminal and unlock the door. The second way doesn't require a high science skill, but you need to the right and the end of the hall and spend some bullets killing a couple Super Mutants, activating the fire switch (I don't remember the exact name) You'll have to kill a couple Centaurs and some crazy guy named Sid. Talk to Fawkes and he'll lead you to the G.E.C.K. (And get it for you seeing as there's a high amount of radiation and you need a Radiation Suit, and tons of Rad-X and Radaway.)

You can't get the GECK by yourself. (Well, you can, but you need to use Rad away like every couple seconds, or use an ass load of Rad-X). The GECK is in a highly irradiated area. If you have him with you, you can have Charon go and get it, or maybe Sergeant RL3 can get it. If you don't have either of them, it's fine. You just need Fawkes.

As you head through those areas, you'll eventually hear someone calling for you attention. Their voice will sound staticey, but don't worry. You'll hear it while going down a certain hallway. Straight ahead is an intercom. If you look in the room, you'll see a Super Mutant. Don't worry, it's friendly. Use the intercom and you'll discover that the creature's name is Fawkes, and she (Yes, she.) will tell you that she was a Vault 87 experiment and was much more intelligent than other Super Mutants. She wants you to get her out of her holding cell, which you can do by heading to the right and all the way down to the end. If you can hack well enough, you can hack the terminal on Fawkes' cell and open it, or in that room you can hack the terminal and open Fawkes' cell from there. If not, activate the fire alarm and all the cells will open. Be careful, as it will open 3 other rooms as well. 3 contain Centaurs, and the other will contain a hostile human. Clean up and go back to Fawkes. She will then lead you to the GECK and get it from the radiated chamber for you. (She also has the unique weapon: Fawkes' Super Sledge. You can get it by asking to trade equipment with her and taking it. She will then equip herself with a normal Super Sledge.) Once you get the GECK, head back, you've got visitors...

Hope this helps.

It is located northwest of Little Lamplight and southwest of Broadcast tower KT8.