A lot happened in March and April. I had a post with much detail written but it got erased by accident. My morale has broken but I'll try to give you a few details.
First in March Lyon's army attacked Polk in NW Tennessee. Lyon proved to be a disaster (1 attack rating) and could not take advantage of his manpower superiority (committed about 55000 of his 66000 men versus my 42000). Manpower losses were close but the Union took more gun losses (including some captured). The details are in the screenshot below that lists all the major battles to date.
No other Union leaders had initiative in March. In April, Lyon was sacked and replaced by Grant, and with McClellan once again not getting initiative, things were quiet in the west. In the east McDowell attacked Manassas and Halleck attacked Winchester. Although Halleck proved to be a decent commander (3 attack rating and 0 army mod), his 20000 men were not enough to beat my 28000 men. Only a portion of each side's forces fought in a small battle that sent Halleck retreating to Harper's Ferry. Beauregard turned out to be a 2 defense 0 army mod leader (mediocre but better than Lyon and McDowell), but Stonewall Jackson made the difference.
McDowell turned out to be another terrible commander (1 attack rating), and his 80000+ man army did not do well against the 60000 Confederates under Joe Johnston (3 defense rating). The Union took horrible losses. Longstreet and Ewell, the two major commanders in the battle turned out to be exceptional leaders, and the Union leaders were a mixed bag of average leaders.
The only thing the Union accomplished in April was the capture of 3 areas of swampland in Florida.

All understanding comes after the fact.
-- Soren Kierkegaard