Assume the longitude reported for your search CS, puts the beginning puts the outer edge of the Maasai's estimated territory slightly short of the area indicated by the Johnson. So the target area, at least as specified by the Johnson, would not have you cross into Maasai territory, but it puts you very very close.
Also, since you are looking for some pretty obscure results, the image search is going to take a half hour of game time to run, but FYI so you can start planning what to do next, it is not going to yield any results.