Trimetric Routing

buy or rent a electrical fishing pole set and wire puller. Lowes or Homedepot and you might need someone who know how to use them to explain how to use them. Just looking at your picture if you have a light or speaker near you run the wire puller toward the wall with a attach loop, then run the fiber glass pole up with a hook screw into the pole and catch the loop on the wire puller. Then attach the cat 5 to the wire puller and pull into the ceiling. The rest should be a piece cake. Good luck and have fun. Take your time and walk around if it goes slow.