I would definitely sleep at Horseshoe Meadows the first night.
Steve, are you assuming the predosing with diamox will avoid sleep issues at 10,000ft camping at HM? His TR indicates that AMS was starting somewhere in this elevation range. Personally, I tend to have trouble sleeping the first night at or above 9k, getting worse higher up. Not a show stopper, but it's draining. I wake up often with shortness of breath, but Diamox may prevent this for him. I was thinking a little lower at the Portal elevation might be more restful. It's worth it to me to drive back and forth, spend the day at HM and drive back down to the portal. He has to drop down to Lone Pine to pick up the permit in the morning anyway. Just my $0.02.
