It occurred to me that I never finished my methodology. When I complete steps 1 through 5 (including all my gear in the weights) and considering step 6, I go back and recalculate mileage and run through the whole thing again. Basically I use an iterative process until I am convinced of the resulting plan. Oh, and definitely take a head lamp along with spare batteries in at least one of your resupply drops.

For trips like this, taking a cue from you wanting to complete the route in the fastest time possible, you need to carry the least amount of weight at any one time. Of course you already know this, but what this means is more resupply stops will be generally better for you as a strategy (depending upon the local situation which you will know better than us). From my perspective, this trip is all about going as light as possible, and fueling your body. In my experience (I have never done 600 miles) the first 5 days will be easy as you burn through your reserves. Then it becomes much harder, so you need to get ahead of the game by eating on a regular basis as you are traveling. Really look at your diet and stay fueled up the entire way because you will need a balance of things that your body will process at a slow, moderate, and rapid rate.

So I'm curious, is this a Florence to Cortina run? What are your start and end points?