I just bought a IDF sling and plan on using it mostly for Drills (National Guard). My unit only has the A2's, so what is the best way of attaching it to the rear stock but yet let it carry at the ready.

you can make a sling loop for the top of the stock with paracord(see maryland ar15 shooters website, they have a tutorial) or get a buttstock sling loop kit from DPMS for about 5 bucks. teh DPMS kit comes with a metal thing that goes around the front tower(ditch this and use paracord) and a thing that attaches to the rear of an a1 or a2 stock and puts a loop at the top of the stock. if you attach to the sling loop at the bottom of the stock, your rifle will want to flip over during carry.