Can someone tell me if I can catch a bus from Yongsan to Cp. Casey? I was thinking of taking the bus from Humphreys to Yongsan and then another bus to Casey. I wouldn't mind taking the metro straight to Casey if someone can tell me which stop is closest to Casey, if there is even one that goes near there?

The easiest way to get to Camp Casey is to take the subway to Uijeongbu station and then take the train (leaves every hour at 20 past) to Dongducheon station (Should be the 4th stop). Camp Casey is a short walk from there.

Once I get to Uijeongbu station is the train to Dongducheon station in the same location as Uijeongbu station? When I leave Dongducheon station which direction should I walk to get to Casey? Do you know if Cp. Casey has a post shuttle?

Yes the train station is the same building as the subway station. Camp Casey is NE of the train stop, the tracks run N/S. So take the road east and when you get to the next major road (2 lanes with stoplights) take a left. Keep on walking and you'll get there.

Or you can take the bus from Uijeongbu Bukbu Station (sometimes Buk Uijeongbu). Exit to the left and cross the road (elevated walkway). There will be a big bus stop there. Get on the bus 36, 136, 39, 139. The bus ride should be 45 minutes or so to Camp Casey.

Quick traveling aid:

Buk = North
Nam = South
Dong = East
Suh = West
Dae = Big, Large
Moon = Gate
(Nam Dae Moon or Mun) = South Gate

There are buses from Yongsan to most all other Posts. Get a schedule in the Moyer Rec Center (AKA Bus Station) They are often faster
than the subway, but much more expensive.

You know, I don't know if there is a shuttle bus on Casey. But there are taxis.
I can't think why you would want a bus- there ain't much to see beyond walking distance of the PX complex. Hint- eat at the Golf Club!