I am not a expert on Nebraska turkey hunting but I am going back for my second time this year. I will be near Verdigre in the far Northeast corner. From that area you can hunt NE and SD. The Indian reservation you can hunt on is called Santee Reservation. I think it gets hunting pressure but a big area with birds and a chance at another tag. This area of NE has Merriams and what they call "hybrids" which look like a Eastern but are smaller and less vocal so I am told. I got on Merriam with a very white tipped fan last year.
This is the booklet I got at NWTF and it has lots of great info in it.
Outdoornebraska.org
Also, there are several turkey guides in NE and if you want to stay in the Midwest I can assure you a great hunt with Terry of Turkey Creek Outfitters in MI
http://turkeycreekoutfitters.com/ or Steve of Steve Hartley Outdoors in KY.
http://www.stevehartleyoutdoors.com/ Booth are great, small, honest outfitters.