Turkey will keep up to 4 day once thawed, so thawing a day or so early is not a problem, if you brine the turkey you need the extra time.
Couple of ways to thaw:
1. Thaw Turkey in its wrappings in a pan in the refrigerator. (no water)
2. Thaw turkey in its wrappings in a container large enough to allow it to be in water. Fill the container with cold water and change the water every 30 minutes. This method will thaw a turkey at the rate of about 1 pound every 30 minutes. An 18-pound turkey will take 9 hours.