New network, simple, I think.

For streaming video and online console games, an ethernet connection will be way better then using wireless for performance anyways.

It wont be that big of a deal if you use the right tools/method to run the ethernet cable.

Since you said the wall is heavily insulated I am going to assume it is an exterior wall and has a firestop at the 4 ft spot. My next two questions are 1) Is the coax run from the basement up, or from the attic down? 2) Is the tv going to be on a stand or wall mounted with wireing in the wall?

Most all states require a firestop in external walls.

Check and see if the coax cable has a hole that is over-sized, might just be able to fish the ethernet right up the coax hole to where the coax cable comes out. There also might be a piece of conduit running in the wall from the bottom wall plate to the plate behind the tv, if the house was built designed for a wall mount tv then it probably has the conduit like i spoke of

Now does the coax cable come out at the bottom or at the tv outlet?

Also, do you need the ethernet all the way to the tv, or just to the bottom plate by the wall?
If you need the line to the tv, i would suggest to run it to the bottom plate, have an ethernet switch and then run a line from the bottom plate to the tv plate, that way you have plates for dvrs, game consoles etc.

Once i know what your setup is like then i can give you better direction.

No problem on the slow response, totally understand being in a move.

I was more wanting to know if there was a dedicated piece of condiut inside the wall that goes from the bottom outlet and the top outlet for the tv (this would be a hollow tube, usually flex plastic or pvc, that runs inside the wall from one plate to another; this makes running cables form top to bottom very easy).

I think you are looking at the back of a fully encolsued wiring box,yes a picture would be helfpull.

In the 5th picture, the piece of wood that the cable goes underneath is that easily removable?

--- No

It would be good to see how big the whole is that goes through the bottom of the wall to make sure it is wide enough for both the coax and ethernet cable.

---I'll see if I can find something to slide up and see how much resistance there is.

How deep is the fireplace? If it is just deep as the extension off the wall then we are fine but if it is the depth of the extension plus 3" then the coax cable was most likely routed around the studs.

---The mantle is 2'3", but it's a gas fireplace; I got a measure of 12" without taking anything apart.

If the fireplace does not go all the way through the wall then what you can try is unscrew the coax from the wallplate behind the tv.
If the box that the plate bots is enclosued you will have to take soem pliers and break the little tab off that the coax cable feeds through.
Take a piece of twine (preferably wire fishing twine that is designed for it) and wrap it around the coax end at least 4-5 times
Now take some electrical tape and wrap it around the twine/cable and go all the way up past the tip of the cable with the tape to try to make it a smooth transition.
Now go down to the basement (if you can remove that piece of wood i was talking about that would be preferred) and wear gloves/sleeves because the insulation is itchy.


---That wood is the wood on top of the 6" studs holding the insulation
see:
http://ridma.com/tomshardware/TV-Stuff/IMG_0302.JPG
http://ridma.com/tomshardware/TV-Stuff/IMG_0304.JPG


Now attempt to pull the coax cable. If all goes well the cable should pull out with minimal pulling/snaging.

If it gets snagged up and mild pulling on it wont free it, then just go back upstairs and pull it back up with the twine, the cable might be attached to a stud, or snagged on something and pulling on it will either rip the insulation off or pull the cable loose from the twine and then you will have your coax cable stuck in the wall.

If the cable came out nice and easy then take the end of the ethernet cable (you can not run a finished cable, you will either have to use bulk cable or cut the end off of a store-bought one) and tape it to the coax really well about 6" down from where you tied the twine to the cable.

Do you have any cable parts/tools?
The wall plates and female jacks are pretty cheap from monoprice.com, if you do not know someone who has the tools then those are fairly inexpensive as well.

This links are all assuming you have white outlet plates and not ivory

Wall plate:
http://www.monoprice.com/products/product.asp?c_id=105&cp_id=10517&cs_id=1051703&p_id=6727&seq=1&format=2

Coax Jack:
http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10426&cs_id=1042605&p_id=6542&seq=1&format=2

Ethernet Jack:
http://www.monoprice.com/products/product.asp?c_id=105&cp_id=10513&cs_id=1051308&p_id=10046&seq=1&format=2

Wall Bracket (only need this if you can remove the box behind the coax cable):
http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10425&cs_id=1042507&p_id=7013&seq=1&format=2

If you want bulk cat5 you can get this, they only come in spool of 1000ft though:
http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10233&cs_id=1023303&p_id=880&seq=1&format=2

Here is the page with various legnths of pre-made cat5 cable, if you do not want to buy the bulk cable you can just get a long one and cut the ends off:
http://www.monoprice.com/Category?c_id=105&cp_id=10208

This is designed to strip the plastic jacket of the cable, for just a couple of cables you could just carefully use a wire striper:
http://www.monoprice.com/products/product.asp?c_id=105&cp_id=10509&cs_id=1050902&p_id=7051&seq=1&format=2

This is a punch down tool, it pushes the individual wires down into the female wall jacks after you have striped and untwisted the ethernet cable:
http://www.monoprice.com/products/product.asp?c_id=105&cp_id=10509&cs_id=1050903&p_id=7041&seq=1&format=2



The twine you can get from your local hardware store. There are other tools/parts for making the male end of ethernet cable but to just run one cable from one wall to another you shouldn't need to make any male ends.


The female jacks will show how to wire them, you want to use the B arrangment, use the sharp edge of the punch down tool on the outside of the jack and it will cut the cable after you have punched it down.