I looked at the profile. Ouch.

Since it is cool early in the morning, I would ride the first two climbs somewhat harder than the later climbs to make as much time as possible and since they are the most difficult in terms of steepness and length. The others are only 7-8%.

Unless you are really fit, you are going to suffer. I would love to do this ride. GL

15,000 feet in 129 miles is a lot. During a climb and overheated, you will digest nothing and probably should eat nothing solid or at least I do not. Once over the top of a climb and you attain say 25mph, stop pedaling, unzip the jersey and cool yourself down and eat and drink. The energy required for the ride is about like a flat double century. I think the biggest challenges are keeping cool enough to digest the rather substantial amount of fuel required.