#1). There has been a drought in the plains, grasslands... things are not at their best so don't expect that. You might start by contacting the Forest Service Office, 125 N. Main St., Chadron, NE 69337; (308) 432-0030 (I think). They have charge of the grasslands from OK north to Canada and west of the Rockies. There is a National Grassland in the SW corner of KS. Probably closest to you. Cinnamon Nat. Grassland. (Cimmaron actually). The law requires the forest service to manage for "multiple uses" which include hunting/shooting. See what they have to say...
I had a buddy who said he had an army buddy who grows wheat just north of the grassland and we were going to go burn up a couple cases of ammo at varmints. He came down with heart problems and that never happened... But he raved... nice guy. Miss him.
BEWARE. (TWO MORE THINGS). i). There is bubonic plague / BLACK DEATH in the furballs. Carried by fleas. Today they say they can save you with much antibiotics and life support... Why bother? Don't handle parts (get a bigger gun or closer!) and let the coyotes clean up... If you must save a trophy, plan accordingly. Flea powder. Plastic bags/ gloves... etc.
ii). There has been the re introduction of the black footed ferret in some mighty fine p'dog areas AND they are OFF LIMITS too shooters. A house cat disease almost extincted the ferrets, poor weasels--tree hugging Democrats (and their Repub allies) cannot do enough for them. All they like to eat is p'dogs, but they hunt at night... regardless, Uncle Sam has restricted these areas. Find them. (Forest Service help) or risk Fed. Slam, confiscation... DON'T. You won't like it...
Oh yes, this is the wide open spaces. You may find yourself 75 or 100 miles from a McDonalds or Burger King or Wendy's or Pizza Hut... . Plan carefully to NOT break down. Bring plenty ammo AND water... It is DRY... and without french fries...
#2). I have heard, never bothered to go, that in OK and TX there are many, many p'dogs, but it is "pay to hunt" and if you don't have the big bucks, you don't hunt. Wyo is FREE. No license. No nothing. Well, gas, grub, lodging, like that. Open arms welcome. You won't hurt an oil derrick with a varmint gun. Thunder Basin is NW of Douglas. CO is full of tree huggers who will turn you in and costly licenses. MT is o.k., just farther. Zortman Garage & Motel used to advertise. NE, nothing organized. You need small game license if you are out of stater. Grand Island west. SD MARKETS! (The "injuns"...) Rosebud Reservation, south center of state, wants you. $125. reservation license. I think 10 days was $25.00. And you need the state small game license... too. Some years guides are required on reservation. North Central, Eagle Butte, Northern Cheyenne Rez. SD Pine Ridge is a mess. They drink to much and fight... but you might find p'dogs. Off Rez, Buffalo Gap Nat. Grassland... beware ferret restrictions. ND is less commercial, farther, drought... luck...