Dear Mr. Lubnau,
Thank you for posting you request on History Hub!
We searched the National Archives Catalog and located the record series Plans and Drawings, 1866 - 1867 in the Records of U.S. Army Continental Commands, 1817 - 1947 (Record Group 393), that includes records relating to Fort Reno, Wyoming. To access these records, please contact the National Archives in Washington, DC - Textual Reference (RDT1) via email at firstname.lastname@example.org. We also located a National Register of Historical Places file for Fort Reno in which you may find interesting, although it does not include period photographs or drawings.
To request a search for photographs at the National Archives, contact the National Archives at College Park - Still Pictures (RDSS) via email at email@example.com.
We searched online and located a drawing of Fort Reno on the web page from the Wyoming State Library. According to the caption on drawing, it is from the Grace Raymond Hebard Papers at the University of Wyoming American Heritage Center.
We hope this information is helpful. Best of luck with your research!