Harrison and the 1st Arkansas Cav was sent to Fayetteville on December 6 to secure the roads and then were ordered on towards Prairie Grove. Captain Harris S. Greeno then directed traffic for the army. Salomon took Blunt's Division and commissary trains to Fayetteville on the evening of December 7 and then returned to the battlefield with ammunition wagons. Surgeon George Hubbard was in charge of the hospitals in Fayetteville until Surgeon Ira Russell arrived and took over.

From the following it looks like sometime later in December after PG, the 1st Ark was occupying Fayetteville.

From Dyer:
Battle of Prairie Grove December 7. Middletown December 9. Expedition from Fayetteville to Huntsville, Ark., December 21-23. Duty at Fayetteville, Ark., to April 25, 1863.