Sorry I found this thread so late...I don't know how much more I can ad...but here goes.
1. Buy Scott Duff's book on the M1/M14...it's loaded with usefull information. IMHO, no M1/M14/M1A owner should be without it.
2. There are several good websites with knowlegeable people (not that these guys aren't, but this is a warbird forum)...I'd start with
www.jouster.com, but there are others as well.
3. Before you shoot it, especially if it didn't come from CMP (sorry, can't remember if it did or not), have a "qualified" gunsmith look at it. I don't mean take it to your local gun dealer, I'm talking about someone who makes their living working on these types of weapons.
4. Don't even THINK of trying to modify it to shoot full auto. Federal prisons are not nice places, so I've heard.
5. Learn to reload...your initial investment will be a little bit steep, but in the long run you'll save many $$. You need to be careful reloading for the M1, though...make sure the loads you look up were designed for the M1 instead of a 30-06 bolt gun.
6. Don't necessarily expect great accuracy, depending on the condition of the barrel, etc. If it doesn't shoot great, you'll have to decide if you want a decent shooter or if you want a historical piece. That decision will determine what, if anything, you fix or replace.
Can't think of much else, at this point, that hasn't already been covered. Congrats on your new gun!
John