We thought March was a good time last year for the center section of the the trail, and though it was a little warmer than normal had no insect issues at all. Compared to the western section we did the previous fall, we had plenty of water and the lack of leaf cover made the views much better.
We will complete the eastern section this March, if that is of relevence.
As our maximum time out was 6 nights, we carried all food and did not resupply, averaging about 12 miles a day. We used a shuttle service through Turner Bend, and recommend their sandwiches, as well.
The section of trail west of White Rock Mountain, and a little to its east, was heavily overgrown in briars when we crossed it in the fall of 2010, following overstory die-off due to the red oak borer. The OHTA can probably give you an update of the current trail status in that area.