The best is buying the wireless transmiter reciver ,you can search in Google to find the brand but that is a good way and easiest

What were you thinking of putting in the non working fireplace? Candles? Stacked wood? A screen?

Yes, slick88gt is right. Having a remote that uses RF- radio frequency- allows you to hide the box and still be able to change the channel, etc. Having a remote that uses IR- infrared- will require a direct hit from the remote, thus needing to be expose to get the signal. So if you can get both on RF remotes, (I don't know how deep your fire place is) maybe go onto Pinterest. I just saw yesterday a cute way to use a non-functioning fireplace. They had stacked thin logs of wood at the entry- it looked great. This would hide the table and boxes behind without paying wiring. Good luck!

With that bump out Fireplace its super easy to hide the wires. Its actually one of the best case scenarios for hiding wires in that layout. Imagine 80 percent of that cavity being open and just "fishing wires to the right or left within the wall.

Once you have your wire problem solved, you may want to consider stacked logs in your fireplace box. I saw someone else suggested that also. I have seen on line where you can order real birch logs, in different sizes. I think they would look nice in the area since they are mostly white, a good contrast to the brick, especially if you get a black log holder. Sometimes just stacking regular logs might look a little to rustic. I know candles are another way to go but to me, they seem out of place in a fireplace and not what the fireplace was meant for. Just a thought.