My husband and I are not the fastest hikers, mostly because he is very affected by altitude. My pace trends around 3 miles per hour, he is closer to 2. We set our time line to leave Whitney portal at 2:00am with our turn around time goal at 11 am. That should give us ample time. We've noticed we roughly have the same pace on the way down surprisingly. I think it's because by that point we are exhausted and walking a little slower. So give or take, that puts us back at camp by 7:00pm. Definitely a long day no matter what.