haha, ok.
NITC is Naval Intelligence Training ?Command?? not sure about the C, but I think it's command. Maybe Curriculum? I dunno, but they changed the name when they changed the curriculum.
You can get your CAC before your first drill. I did, and I recommend it. Depending on your options, it could take a couple of hours of waiting, or less than 5 minutes. Took me all of 15 minutes since I have a small Army site near me with DEERS access. Go here to find the closest place to get an ID:
http://www.dmdc.osd.mil/rsl/owa/home You'll need your oath of office, ID, and I forget what else. Call them first to see if you need an appointment.
It took me 12 months to start NITC because of clearance issues. Long story, but it was crazy. The other guys waiting are for other stupid reasons. It really depends on your chain of command giving you the "OK" to start, and having your clearance squared away. The latter being completely out of your control after clicking "submit" on eqip.
DWE = drill weekend
The pre-reqs are all kinds of things. GMTs (General Military Training), having all of your medical stuff done so you're good for the next year, having all of your various website accounts setup, having your NMCI email functional...just a lot of stuff that can't be done until you're in the system and drilling, but that can't be done efficiently if you're away from your home unit.
After indoc, you should avoid NOSCs as much as possible.

They're a giant CF of admin. I only ever deal with the NOSC if there's an issue with my paperwork, which has been way too often. KEEP COPIES OF EVERYTHING.
It's not a choice you get you make. SD is where I was told to go, so that's where I'm going. Like I said, I've only heard that Damneck was the site for some people, but can't verify it. You'll find out eventually.
Your unit is pre-determined, at least before you get your 9600. Before you get it, you're in a training status and only specific units take those guys on. Up here in the northeast where there are quite a few intel units, a couple of them don't take guys without a 9600. Besides, when you start out, you want to be close to a clinic/Dr., and close to the NOSC because things will go wrong and they're the guys that can fix it.
Once you get your 9600, you can start finding other units to drill at if you'd like. Some units have more than one mission, though, and you can change jobs without leaving your unit. It just depends on what the capabilities of your assigned unit will be.