I just put it alongside base of wall, and it has to go across my hallway, I put a mat over it in the hallway. In the living room where my phone line is as well as my gigabit router, its behind furniture hugging the wall.
Its doable if motivated enough, shouldnt need to put under carpets to keep tidy. Granted tho I dont have anyone living with me to moan about it
If its on a different floor I would consider putting up the outside wall, I did that at a previous address and rain snow etc. never affected it.
BT Infinity 2 Since Dec 2012 - Estimate 65.9/20 - Attainable peak 110/36 - Current Sync 71/20