The earlier you get there the better! If you plan on making a decent amount of noise I would say get there about two hours before first light...hope for a bright moon.
You have to remember that turkeys live in the woods, and there are ALOT of animals running around under those trees at night, so if you get there way before first light when there is still nocturnal animal movment and keep your noise to a minimum you should be alright.
I would steer clear of using a flashlight, and if you do try to keep it very low key. The best thing to do is to hope for a really clear night with a bright moon and get out there as early as you can, especially since you are setting up a blind.
Good luck and I hope this info helped