The Pine Ridge Nat. Forest near Chadron Neb. has alway had good numbers of turkeys over the years. You can get more information from the USFS headquarters in Fort Robinson Neb. about the number for this year and to get maps and DIY.
I'll second the Pine Ridge National Forest or the various WMAs around it, especially Bourdeaux Creeek. But that's a little close to Chadron. Gilber Baker is a another real good turkey spot, but it's rugged as heck. The NGPC is food plotting again which helps to keep the turkeys on the state properties.
There can be too much of a good thing with antler rattling.
I like to hit the horns together for a good 30- to 40-second rattling sequence and then hang them up and resist the urge to hit them again.
This works to the hunter's advantage, because if a buck has heard it, he may have been 300 or 400 yards away and he comes in and he's not exactly sure where it came from.
When finally is time to rattle again throw a slight change-up into the routine.
The second time, don't rattle as loud...