You don't have ANY internet connection?
No dial up? No cell phone with a hotspot feature? Nothing?
The reason I ask because you don't have to be online all the time to play Steam games.
Buy the retail version and install. All you have to do is be online to unlock the game. Then you can go into off-line mode and play off-line.
I think you might have to log bakc in every month or so, but it's definitely doable on dial-up.