I added a wifi and cellular antenna to the mast on my boat. I reused the existing wiring access hole and bought a new piece of inside plastic to drill out inserts for the new and existing cable runs. From there, I was able to use a snake and route all the cables across the top front of the boat where the storage cubbies were.
I then ran the wires down the A-pillar of the starboard side windshield and followed the CB wire down into the rear electrical cubby behind the dash. I did not need to take down the roof or storage bins, but I can't say it was quick work; it took several hours (or was it days) and lots of "I give up and bringing it to someone to finish." I used both a circular ribbon-style snake tool and a tent-rod style, as well as some plastic pry bars to open the areas up.
Good luck - they don't make it easy.