That's pretty nifty, Vin, but spendier than my plan. Haha.
Here's what you'd need for my plan:
One of these
on both ends (most likely; you could try one to start and see).
One of these.
Your 100' run
. Your 50' run
. Your coupler
. (Yes, unfortunately NewEgg doesn't have 150' Cat5e runs. You can search elsewhere though; I found this easily on google.
So, anyway you look at it, you're looking to spend well over $100 (if you factor in shipping).
Here's one more alternative, but spendy. You'd still need the 150' cable.
Oh, and one more very cheap suggestion. Does your friend have a laptop or netbook? If this place has a wireless connection, he could easily use a remote desktop (such as LogMeIn) and control the computer hooked up to the TV. That'd be pretty simple, and if there's internet at all there, that'd definitely be the cheapest way to go (you can get a Wireless-N router for like $35-40 bucks).