Regarding your first statement, "I interpret the last correspondence meaning that Col. Gano was returning from Tennessee with his Squadron of Grapevine Guards to resupply at Bonham."
If you speaking of the Nov 9th letter from Steele to Anderson, I disagree with your conclusion. I believe Gano had already been to Texas and went back north to his new brigade, formerly Bankhead's with the addition of some transfers from Cooper.
Gano reached Camp Hardeman from Texas, with a company of men, to take over his new brigade. Perhaps this 'company' was his 'Grapevine Guards'. It is my belief that Gano was traveling north from Texas to his new brigade, arriving on Nov. 1st.
You don't share you source on your statement that the Grapevine Guards were enroute to Texas in November or that they were moving south on the Ft Smith-Ft Towson Road. I have to state that I am unfamiliar with Gano's prior service and the Grapevine Guards. However, you know of course that Ft Smith was in Federal control so they would not have passed through Ft Smith. It is unlikely that they used the Ft Smith-Ft Towson Road as Cooper reported about December that the road was rarely used, unmaintained, and could not be used by wagons without considerable repairs. It seems unlikely they were traveling without supply wagons. It would seem more likely to me that they entered Texas via Laynesport or Shreveport.