i did the grand tour in 1998. it was my only double century and the year i was injured.
203 miles, 4k elevation and 16.2 mph average. i flatted at least three times. i got about 2 hours sleep the night before and before i was done i knew i wouldn't need to do another double ever again
i remember we pulled up to a couple of gals near the end at pepperdine who weren't on the ride. they asked us about our ride and they were shocked that we had ridden more than 200 miles that day.
originally i was going to do the davis double that year --which is nearer my home -- but i got sick and i gave my number to a friend.
the grand tour is one of the easiest doubles in the state and it was an interesting course. i strongly recommend it. i still have the tee shirt in my closet hanging next to my tattered death valley century tee (rode that one on my 41st birthday).