My thinking is that maybe he became involved in the events in Arkansas during the Springs of 1862 and didn't return east of the Mississippi.

By April and May of '62 the military situation was a total mess in Arkansas because of Van Dorn and he wasn't liked very much. His abandonment of Arkansas in April almost caused the Governor of Arkansas to recall all Arkansas Troops in the Confederate army home and secede from the Confederacy and the United States both.