We got maybe 50% of the stakes into the "ground" and piled rocks to secure the other points/lines of the tent. (See 2001 trip report under the "highpointing" section of my <a href="http://www.mtritter.org">WWW site</a>.) Not a problem...plenty of rocks around. Just be careful when you select your tent site...some of them drain, some of them turn into lakes if it rains. (I picked the right one...our neighbors didn't and got soaked overnight...)
Also, I'll have to disagree (respectfully) with "GonnaSummit" and say that I was very happy that we went all the way to Trail Camp. Fewer mosquitos than Outpost and cutting six miles off the summit day was critical to our making it up and off the summit before the afternoon t-storms popped up. We had acclimated a couple of nights at Mammoth Lakes (8,500') and hiked to 11,000' before we drove down to Whitney Portal, so we slept reasonably well even at 12,000' at Trail Camp.