Excellent point about Little Rock being virtually abandoned by the authorities during a brief period in May.
Here is some pertinent correspondence form Vol XIII of the Official Records that give an indication of General Roane's dilemma.
PINE BLUFF, May 4, 1862. Major-General VAN DORN, Of Trans-Mississippi District:
I write you from this place, where I have been shipping troops from Texas. After having shipped you all the regiments and companies I could find in reach, and directing each shipment to report to you, I now submit that I have just received dispatches from the Governor of Arkansas and my adjutant of the fact that the enemy had reached Grand Glace, on White River, with their advance, and calling on me to take steps for the defense of the State. It is my opinion that I cannot with safety send any more troops out of this river, believing they may fall into the hands of the enemy, and that the valley of the Arkansas and the whole State is in danger of being overrun by the enemy. If his progress can be staid until you can fight the battle of Corinth, we can then expect you here with what aid you can bring, and your own experience and superior knowledge, to drive them out of the State. It is possible to make some resistance, as there are still some resources to be availed of, and, in the absence of further orders from you, I shall proceed to act as I believe you would order, and as I believe is for the public interest. The Texas regiment, said to be on its way here, cannot get to you, and I will employ them with all other means I can control to oppose the enemy until otherwise ordered. What further steps I shall take to raise proper force, and to concentrate means and material for that purpose, I can better determine when I reach Little Rock, to which point I shall repair immediately. I will there report to you, and will continue to do so by all opportunities. In all things I beg you to believe that I will, to the fullest extent, carry out what I am bound, in your absence and isolated as I am, to believe would be your wishes. In taking so great a responsibility, so unexpectedly thrown upon me, I shall rely, my dear general, upon your sympathy and your support, as I am determined to do all in my power to deserve it.
No orders for enrollment under the conscript act have reached here, and, if enrolled, the conscripts cannot now pass to the regiments beyond the Mississippi; neither does that act prevent the President or repeal his power under other acts to call on the people for troops in urgent cases; so, if I shall judge it wise, I may raise more troops, but I will not do so unless I believe I am compelled to do so. The position is new to me and the responsibility great, and I wish you were here, but I will consider maturely and weight well beforehand every step I take. I pray you, then, to give me the aid of any advice and assistance that you can.
I have discovered a small lot of ammunition, which I can control, at Little Rock. The Government has large numbers of mules in the neighborhood, and it is more than probable that means of transportation can be obtained for what troops I can procure. The greatest difficulty is likely to be in the matter of subsistence; but I shall hope it may be obtained. I feel satisfied, as you have been called away from your proper command, that you will approve every effort I can and may make to preserve and protect it from the enemy until you can return to it.
J. S. ROANE, Brigadier-General, C. S. Army.
LITTLE ROCK, May 10, 1862. Brigadier General DABNEY H. MAURY: No troops have reached Arkansas River except six companies of Parsons' regiment; two companies have been forwarded, other four detained here, it being deemed unsafe to ship troops to Memphis since the fall of New Orleans, and in the absence of instructions from your headquarters, for which I have repeatedly written. Also General Curtis' command, reported 22,000 strong (in my opinion not more than half that number), are at Batesville and Jacksonport, moving to this place and valley of Arkansas River, and I thought with the Texas troops and such others as I could raise in the State I could hold the enemy in check until you could whip the Federals at Corinth. I was unwilling to see the State abandoned and overrun without a struggle. Johnson's brigade will be at this place in two or three days, so I am informed. Unless otherwise ordered, I shall send no more troops to Memphis. I await your orders. J. S. ROANE.
HEADQUARTERS ARMY OF THE WEST, May 11, 1862. Major General J. S. ROANE, Little Rock: I am directed by General Van Dorn to say that he wishes you to assume command of the forces for the defense of the State of Arkansas. You will please therefore at once take proper steps to organize and put into the field all troops of that State brought into service under the conscript law, and all cavalry forces from Texas and from Northern Louisiana who may come into Arkansas to report to General Van Dorn. All the companies of Parsons' regiment of cavalry which may have come over the Mississippi will be ordered back at once. Any infantry troops who may come into the State or who may be already organized there to serve under General Van Dorn will be forwarded to his army as rapidly as possible. Steps will be taken at once to furnish you with all ordnance stores which may be necessary.