Did this yesterday. One of the hardest one day rides I have done, considering the heat and humidity. 100 miles and 10,000 feet of climbing, including 8 miles up Mt Greylock.
I probably drank 12 bottles of cytomax and ate a few gu's and cliff bars so I did'nt cramp up but I was definitely close to heat exhaustion between 55 and 80 miles. I lost 4 pounds. I'm ready for the Catskills Century!