I'd stay at least 100 yds from the roost if you do locate it... other than that, sounds like a solid plan. Don't set up your decoy directly in front of you (i.e. a straight line from your position), have it off to the side a bit, just in case someone decides to shoot it. Also, if the turkey is keyed in on the decoy, you won't be directly behind it, in the turkey's direct line of sight.

Other than that... wait until flydown to call, call sparingly and don't move.

If you can't locate the roost the night before, then you'll probably have to walk and use a locator call for shocks.

Not much else I can do from here.