Notice on your map that Ft. Kearny, WY has no “e”, while Kearney, Nebraska does. Named for the same guy!
That's one of those "Huh?" moments in history. No, they're named for two different people; Gen. Stephen W. Kearny (Ft. Kearney, NB) and Gen. Philip Kearny (Ft. Phil Kearny, WY).
Yes, the name was misspelled on the Nebraska post. Apparently the misspelling continued to be used officially, and it finally became recognized as the standard spelling. Go figure.
I've visited Ft. Phil Kearny and the Fetterman site but never got over to the Wagon Box site myself. At the time, the post had been surveyed, but that's all. I understand they've made it more interesting. At the time, there was little there except a welcome center/bookstore.
The one thing I've never got beyond, is how 2000 Indians could conceal themselves to ambush Fetterman on that narrow ridge. We were there in late May and the grasses had to be grown to a further extent than in December. I just couldn't understand how so many Indians could be so well concealed. Even the gullies didn't seem to provide adequate concealment. Oh, well.