I had a similar experience to natewalsh above and as he notes its a common issue. It doesn't always require the frame to be drilled but it I had to remove the BB and really fish around in the frame to re-align thing which took age. Last I checked the outer housing felt like it was stuck again so I will only be replacing the inner cable the next swap.
What I did notice when I swapped out the cable was that the outer was still in really good shape. If you do find yourself with a stuck outer you should be fine just to replace the inner. The only outer cable on the Transition that really takes a hammering is the rear brake where it pops out under the BB.
In terms of cable housing I can't remember the lengths as I used the old cables as a template. The front mech is important to get right though because the cable has an internal stop within the frame. If you go to long or too short you will have a headache getting the inner cable to come out the frame. The trick is to insert another cable into the exist port so it running the wrong way through the frame. Then use this inner as a guide for the new outer and inner. The same process works well for the rear mech cable in getting it to exist properly.
Fingers crossed nothing sticks and then it is a very straight forward process. If you do run into issues force is unlikely to be your friend.
Great tips! Crazy how this helped spark back tons of memories from the last time I did it. Thanks for the help!