[5] Rhodes' post-Indian Wars assignments included professor of military science at Ohio Wesleyan University[6] and commander of a cavalry troop during the China Relief Expedition.

[9] The DSC citation reads: The Distinguished Service Cross is presented to Charles D. Rhodes, Captain, U.S. Army, for extraordinary heroism in action near the barrio of San Nicolas, Pueblo of Bacoor, Cavite, Luzon, Philippine Islands, December 31, 1901.

Captain Rhodes gallantly and fearlessly led an attack on a superior body of insurgents with two men of his troop, killing two of the enemy and wounding two, including their leader, and dispersing the remainder.

[12] Later in 1911, Rhodes and Paul Bernard Malone took part in a confidential mission, traveling to Mexico disguised as journalists to assess the likelihood that Francisco I. Madero could remain in power if he won the presidency in the 1912 election.

Later he served with distinction as a member of the Inter-Allied Commission at Spa, rendering conspicuous services to the American Expeditionary Forces.

His works include: History of the Cavalry of the Army of the Potomac (1900); The Vicksburg Campaign (1908); Letters of a West Point Cadet: An Epic in Blank Verse of the Class of 1889, United States Military Academy (1935); Chief Joseph and the Nez Perces Campaign of 1877 (1937); and Diary Notes of a Soldier (1940).

Rhodes retired from the Army in 1929 and resided in Washington, D.C.[31][32] He died at Walter Reed Hospital on January 24, 1948, and was buried with his wife Mary Counselman (1867–1943) at Arlington National Cemetery.