re: Working on an M1 Garand yourself

If it were me and I didn't already have one, I would order the field grade and prepare to replace the stock. You can buy the same ones the CMP puts on their specials directly from them for $157 (complete with all the metal). LINK

I wouldn't buy a new barrel until you've had the chance to shoot the one you get. Even barrels with a bit more muzzle and throat wear can still shoot incredibly well.