I also have used the coat hanger trick many times at home and other places to explore before you do major excavation. A relative of mine drilled a hole in a wall to run a cable. He hit a water pipe and it caused extensive damage before he could find the shut off valve. I always explore with a coat hanger since there may be hidden ducts, wires, pipes, or hidden fire breaks preventing easy vertical routing of a cable. Another trick is to cover up an excavation with a fake heat vent, fake (or real) speaker grill, or something else.
Another trick I have used is to take a long piece of metallic electrical conduit, and cut 2 or three "teeth" (notches) in the end and sharpen them. Chuck up the conduit and you have a ten foot drill bit. You may be able to get through a few 2x6 's before it needs sharpening IF you are LUCKY. There are also very long drill bits available in electrical supply houses, and even sometimes in box and hardware stores. Some are 2, 3,
feet or probably even longer, but they tend to be expensive.
I have run electrical conduit outside of buildings in a few cases where I did not want to disrupt or spoil the inside of buildings. Also, often I run my ham stuff outside then enter the house somewhere it does not get an automatic veto from my wife.
Also do some research, there are coax and other cables which are not black. Sometimes white is available.
I am not a professional sheet rocker, or schooled in texturing or painting, but with a bit of practice I have cut out many holes in the walls of my Church to run eithernet, power, and microphone cables all over.
With a little practice most people cannot even find where I put in patches. practice a bit in a closet, garage, etc. before you try this in your formal living room.
Rick KL7CW