I just did this and would recommend not replacing the cables if you don't have to. Just swap them out with the new controller head pulled out from the dash just enough to access the cables, fairly easy.

( I bought a unit off the auction site and after running the cables I found that the seller had cut the cables and they were all 1" too short so I had to reinstall my old cables and use them.)

Otherwise just run them in the most direct manner to the exit hole in the frunk metal.