Hi. So, Picacho and I (apparently with nothing better to do) have been investigating this claim by Harney Peak to be the highest point east of the Rockies and west of the Pyranees:

See also, if my image insert attempt isn't right, this web site:
http://durangoman.com/hiking/highpoints/highpoints_midwest_sd_hike.htmlHere's the lat/long for Harney and Big Bend's own Crown Mountain--the REAL farthest east 7k mountain:
Harney 43°51′58″N 103°31′54″W / 43.86611°N 103.53167°W
Crown N 29.260479 and W -103.259897.
Picacho points out that Harneys W long roughly corresponds to Study Butte, so the entire Chisos is further east than Harney.
Also, Picacho points out that the highest peak east of the Rockies is Laughlin Peak in New Mexico; and I add, there are a bunch more, such as Capulin volcano in NM.