I am unable to access the internet on my PS3 via any means. It's is not close enough to our routers (in separate rooms), I cannot run it on the TV in the room the routers are in and the TV I am using it on is not portable.

So I am wondering how and if I can update The Elder Scrolls V: Skyrim via USB and where I can download said update from (direct links to safe downloads if possible please) thanks!

it's impossible , you can only update
ps3 games on psn .

it's impossible , you can only update ps3 games on psn .
you have to connect the ps3 to your internet , sign up for a psn account and start the game while online to update it

if you can't access your wifi or move the ps3 and/or tv then buy a long enough ethernet cable and connect wired
you can run the cable behind furniture , drill holes through walls , run it out a window and down to a lower floor , whatever you need to do , or call your service provider and get the connection moved so your router can be moved .
whatever you have to do , buying a 50 foot cable ( they're really cheap , or so ) buying a better router , it has to be connected to update games
you can connect , sign up , update and be done in 30 minutes then if needed disconnect it all again .

they'll never put ps3 game updates online to download because hackers would access the updates and hack the games code , these updates are many times to stop or patch cheats so they aren't going to allow people to get them any other way than from psn where it's secure