Hi,
The last time we went the 2nd week of March, 10-15th (just dh and I then) the park was not really that crowded. That said, I had always gone during late July/early August. The early part of the week was perfect, things started to get cramped by the end of the week when people started coming during their Spring Breaks. I think that we didn't have many problems because we used FastPass effectively and got to the parks pretty early.
Iheoma