My daughter was/is (undergrad and now a masters) in history at Wyoming. I don’t think any of the professors specializes in medieval history, but they are very into allowing students to study whatever they want. They also have a pretty nice study abroad program (subsidized by the Cheney family) and participate in the program where students can do an exchange program at other participating US colleges for the lower of the Wyo tuition or the other school’s tuition.
My daughter’s thesis is on the presentation and display of Tibetan art, and none of the professors specialize in that!
As for how close it is to Washington, well it isn’t, but I’m sure there are a lot of students driving that direction all the time and could get him close to home. Wyoming is so big that a lot of students have cars on campus JUST to drive home when they need to as it would be 8-10 hours. They drive to campus, park in an outlying lot and pick up their cars only to go home. My daughter had a friend from Denver who went to school in Idaho and she dropped my daughter in Laramie and traveled on to Rexburg. All kinds of arrangements to get to and from school. The first trip is the hardest, but after that it works out.