In July, 2001, it took Nathan (then 12) and me about 5 hours from Trail Camp to the summit. We had hiked in the previous day and camped at Trail Camp in order to have a shorter summit day. That worked out well because the thunderstorms blew up as we were between the summit and Trail Crest on the way down, so we probably wouldn't have made it if we had started at Outpost.
Our hike (with full packs) from Portal to Trail Camp took us about 6 hours, including a good 45 minutes of waiting at Outpost for t-storms to clear out. From Trail Camp back to Portal the third day took maybe 4 hours, although the last mile or so, when you can see the cars in the parking lot but still have a bunch of switchbacks to go down just above the Portal, seemed interminable.
Trail Camp is pretty barren, being above treeline, but the views of the mountains along the ridge more than make up for the lack of trees. There should also be fewer bugs up at Trail Camp. Outpost has lots of grass, trees and water around to encourage insects.
2001 trip report is under the "highpointing" pulldown on my <a href="http://www.mtritter.org">WWW site</a> with photos and panoramas.