I believe it was Pogo who said, "We have met the enemy and he is us..."
You have not finished your homework and as is, you are deluded. 2,000 rounds a day? That "set's the bar" AWFUL high. Maybe you missed the weather over the last decade. There has been severe drought in the high plains, the grasslands, etc. The low density population areas do not get news/weather coverage comparable to more densely populated areas. In nature animals live in cycles. With drought and low food the females have fewer pups, the males lack energy, disease gets going... In addition to the standard poisoning the government has been doing for about a century... When every thing is GREAT, in a couple years, MAYBE, then you might see that kind of shooting once in your life. Time to start looking, as said, is now.
South Dakota MARKETS! The regrettable truth is that they do not care to tell the "whole truth" when it would hurt business. Thus the advice to hit the game rangers, government biologists, etc. Plague has been a problem. With cattlemen wanting grass for cattle in drought, they have encouraged poisoning. Can't blame them. Don't like it. There is the "black footed ferret thing." Areas closed for a weasel that was about exterminated by a house cat disease. Shoot there and it is Fed Slam. Don't. Google Rez names, Rosebud, Pine Ridge, Standing Rock, Lower Brule, for current info... but don't forget, SW corner is public land, Buffalo Grass Nat. Grassland... Wide open except for the ferret thing. Very wide open. Go in pairs and try not to break down or run out of gas. And bring MUCH water.
If you examine "Indian" as in Native American politics, you will be reminded of Chicago, NYC, K.C., ... They fight among themselves. Some are in favor of selling shooting to shooters. Some are not. Rules change. Google the Reservations and keep current. Pine Ridge has a drinking problem much covered in the newspapers. Beware of the unreliable/intoxicated.
There are p'dogs throughout the grasslands. Mexico to Canada. Gun laws make shooting in Mex or Canada --forget it. Tx/OK is pay to shoot. For the Rich. In ND, SD, Wyo, MT, the ranchers will beg you to come shoot in good times. Drought is not "good times." Still they wouldn't mind the company but 2,000 a day. Sorry. There is a Nat. Grassland ["Cinnamon?" personal joke. Cimmaron, actually] in the SW corner of KS. In better times many p'dogs. CO has them but they practice "catch and release" covered on t.v. no less. Then there is that vacuum truck that sucks them out of the ground for transfer... Wyo is wide open. You won't hurt oil equipment with a varmint rifle although you might get lynched for trying. Cheyenne is full of tree huggers. Get outside the booby pond... Nothng organized in NE. Ron Scherbarth is a noted sculpture/taxidermist. Google him. He could stuff you a rat... At one time, ND grazing assoc. was begging for shooters. Gas was cheaper and no drought... Near T. Roosevelt Nat. Park. (BUT not IN THE PARK!). I prefer Wyo. No license needed and wide open arms welcome from chambers of commerce. Once saw a list of ranchers put out by SD extension. OUt of date now if I could find it.
Keep digging. Don't get lazy or fooled by the Rez talk. (lakotamall.com has another guide). VHA has a magazine with guides. [varminthunters.org ??] It is worth the investment in time and with the price of gas coming down. Actually it is not too late now. Barring early winter, some of the best travel/shooting is after Sept 15 when the tourist traps close and the educated dogs are still feeding. Longer shots but more challange/fun... You are right, plan, plan, plan... the ENJOY! luck.