Hey Steve,
Pantherophis emoryi is the great plains rat snake. It sounds like your field guide may be from the 90s or so before all of the more recent taxonomical changes. Elaphe guttata, now known as Pantherophis guttata, only refers to the eastern corn snake which is a close relative of the great plains rat snake.

The snake just does not look like any young obsoleta I have seen. The pattern and overall brownish color makes me lean towards emoryi, though I know young obsoleta can be sort of brownish. The chief reason is pattern on the head. They are in the same Genus and it can be difficult to tell the young ones apart.

I am mainly into Asian rat snakes and Latin American racers so I am not as familiar with these snakes as others may be, but I feel I know a decent amount. But like I said earlier I could be wrong, lol.

John