iPrototype wrote:1) Using Steam, will the download be available at Midnight EST
Possibly.
It's up to 2K to set the unlock date and time properly though. If they don't (in other words just list the date), Valve has to unlock it manually. So it could be 3 AM or 9 AM or Noon, whenever someone gets into the office and does it, but you can play it at some point during that day. They might do pre-load but I highly doubt it.
2) Do you need to have an active internet connection to play?
Once you download the game, run it once to verify the cache. Then you can set Steam to offline mode. You need to go online once every 30 days.
3) Do I need Steam on a computer to run the game? My plan is to download it, place the files on an external and run it from there on my Bootcamp partition in my Mac.
Yes, you need Steam installed. But this is a good thing because you can then play TF2 in both Windows and Mac OS!
You can move the games to your external drive though, you just need this:
http://www.traynier.com/software/steammoverAlternatively, you could just install Steam to the external drive and it will automatically install all your games to the external drive.
Do note that you'll get mildly better performance running the game off an internal drive. Especially the SSD in a MacBook Air. (As to the overall gaming performance of an Air, I cannot speak to that.)