first thing i would do...is get into those woods when the birds are buggin in the field...(come in from the backside of the trees so the turkeys dont see you)...and look for their roost area...preening feathers on the groundand droppings will tell you your very close...then set up within a hundred or so yards since your not sure which way they fly down..
If you cant, try the slough edge for your set up (bring your dekes and place them in the field assuming you have brush you can hide yourself along that slough)..as close as maybe sixty yards to the treeline...that's a good start...good luck