So I've read that steam will sometimes try and download the game even though the disk is in. Assuming I don't have this problem, or work around it, what sort of install time should I expect? Only thing I ever used with steam was half life 2 and that was years ago so I don't really know what to expect, I just know the wait, no matter how long, will be awful. Just wondering how bad I should expect.

Well it's just short of 6 GB it'll have to download if you let it download everything. I don't know how much the day one patch will be that you'll probably have to download anyway even if you can install from disk.

This page may be helpful: https://support.steampowered.com/kb_article.php?ref=5357-FSQM-0382

Most Steam games install very quickly, even retail disc versions. MW3 retail took me about 15 minutes. Digital downloads are pretty much instant besides a the usual directx installs, etc.

I forgot to mention, I preordered the game from GameStop. So I guess there's no way I could preload?

You could cancel your Gamestop preorder and buy it on Steam instead. The pre-load is fairly painless and has the advantage of being ready immediately once the game launches. You won't get your special preorder map, though.

If the game gets delivered early, you can register it on steam. It won't allow you to install from the disk but you can then download it for a pre-load, it's a strange system.

There was a post detailing how to make steam install from disk so as to avoid the download.

You're looking at 30 minutes tops, unless the server gets overloaded. And it didn't for MW3, so why now?