By the way, here's how to fix the problem of most of it being on private land:
1) Map as much as possible. This allows focusing on areas of highest interest.
2) Combine everything that's public land into one bundle. Preferably, hand it over to the natives; or if that can't be made legal, make it a national park.
3) Set up a visitor center as planned, so people know how awesome it is.
4) As soon as enough information is available, get someone to write about the second-biggest city in historic Turtle Island. Ideally we'll want a children's book, a lay reader for adults, a coffeetable book, a comparison of Etzanoa and Cahokia, an academic book -- and at least a pamphlet or something written in Wichita, the language of the city's likely descendants.
5)Offer perks to private landowners who wish to share their site with other people. Let them charge a fee, and keep a list of paid tour sites at the visitor center. Tourists can visit the public part for free and the private plots if they have pocket money.
6) Fundraise, apply for grants, etc. to create a land development budget. Let local landowners know the area in which the foundation wishes to buy land as it comes on the market. Encourage everyone to offer right of first refusal to the foundation at fair market rates. Buy as much land as possible, adding it to the core of public land.
7) Let local landowners know how to make living donations and bequests. When someone gives land to the foundation, name it after them (or let them name it as they wish) to commemorate the occasion: "Mr. Generous Smith Ridge." If the land can be returned to tribal hands, we can also advertise this as fixing what's broke in America today.
8) Invite the many collectors of local artifacts to sell or donate their collections to the foundation. Even out of context, these artifacts have some value, and there are mass quantities of them. Ask collectors the best spots for finding items, which will be some of the best excavation sites. Name contributed collections after the collector(s) if they wish.
9) Ask around and see if anyone wants to host a powwow. It's their history first. Let's make a honking big deal out of ancient civilization. (Remember, Cahokia was bigger than London at the same time period.) This will attract more attention.
10) While we're at it, offer internships in the digs to native students. Let's get some tribal archaeologists. They probably have a better cultural base to understand what's going on there, and it neatly avoids the "white people digging up red people's ancestors" problem. Plus if they run into a curse or something, they're more likely to recognize it and know appropriate safety precautions.
A lot of this is actually similar to how Grand Prairie Friends works, and our holdings are growing like crabgrass.