"I'm sure that THOMPSON and friend BRONAUGH, with only 19 months in Arkansas, were loyal to their home state of Virginia."
This well may have been Thompson's purpose of organizing the 1st Arkansas, since Virginia seceded on April 17th. But I would think that it takes far longer than just two weeks to gather several hundred men together and getting them organized.
Therefore I feel that maybe Thompson and others were simply caught up in the "War Fever" that was sweeping the south at the time especially after the events of Fort Sumter earlier in April.
As a matter of History two previous secession Conventions had been held in Arkansas which had resulted in votes to remain in the Union, prior to the third convention which final passed an Ordinance of Secession in responce to Lincoln's call for 75,000 volunteers to put down the southern rebellion.
So loyality to Virginia may have been a individual influence on Thompson and Bronaugh. But Lincoln's proclaimation had far greater influence on the general population of Arkansasawyers like Roane and MacGregor. I know that Roane and MacGregor weren't native to Arkansas, but they had made it their home.
"THOMPSON' bio says he requested his regiment be sent to Tennessee for action. Is that documented,?"
I am not aware of any documentation as to why Thompson would be credited with such a claim as wanting the regiment to go to Tennessee. However, the day after the people of Virginia ratified their Ordinance of Secession the Union Army occupied Alexandria, Virginia. Making it the first state to be invaded by the Union.
They made a general call for volunteers from all states to come to Virginia for the defence of their state and the Confederacy. That is, in my opinion, why the 1st Arkansas went to Lynchburg.
As for reading materials there are several histories of the 1st Arkansas Infantry which have been published. That may have been the reason the Bryan Howerton did not include that in the gerde's 1st arkansas page.