In "getting there" you said "... at Road's End - you can take either the side of the creek....the right side ( when looking east ) being shorter, but in the sun...The left side is a little longer, but may offer better shade." I was there 10 days ago. Looking east, the left (north) side looking east that is about 1/2 mile shorter and sunnier. The right side (south) is a little nicer, cooler, and longer - you have to go a little west from Muir rock, from the south parking lot, and cross a bridge for the south side route.
It might be a time of day or time of year thing then. I specifically remember baking in the sun heading out on the south side and enjoying a cool hike in the shade on the north side when coming out. As far as the length, it was hard to tell while doing it - but, I got that info from the ranger. It felt long both ways to me ... on the way out from the heat, on the way back from being dead tired :)
"Got tight last night on absinthe and did knife tricks. Great success shooting the knife into the piano. The woodworms are so bad and eat hell out of all furniture that you can always claim the woodworms did it."