Not that simple.
Let's start with the basics...
1. You can't simply put a bunch of heated electronic gear into a cabinet and shut the door. It will suffocate the gear and it will promptly die. No, I'm not kidding. In my time in AV the number one killer of consumer electronics is heat related due to poor cabinetry. You must use a cabinet with vented face, back, and/or sides and properly space out your gear inside the cabinet. If you have that cabinet... then yes!
2. One coax going to the TV will happily not deliver HDTV to it, only modulated video or standard composite video. The two worst forms of video possible. Typically, to a modern TV setup, I recommend at least the following cables be run: 1 HDMI cable, 1 component video cable, and 1 composite video cable. If speakers on the TV are to be used, then run audio cables as well. The receiver you have may convert all incoming video to component video output, so you may be able to just use component video to the TV... Which is fine to use if you are not talking about the setup above the fireplace.
3. In any permanent install, like over a fireplace, don't be cheap. That is, do it once, and do it right. Run every cable you will need now, or in the forseeable future. This may include VGA, HDMI, component, s-video, and composite. Perhaps CAT-5 for later networkability (cheap)... maybe two pieces. Perhaps conduit to allow for future cable runs... maybe.
If you just use composite video, or worse, RF, then you will only get the lowest possible video quality available to you. This is not at all recommended.