Bikerchuck

I am planning on doing the TransAm route from Astoria to Yorktown this Spring. I will be fully loaded, self-contained. Riding a 2013 Trek 520 with Avid Single Digit 5 V-brakes (linear pull). Currently has the Avid pads but I am concerned with the ability of this setup to be able to stop when fully loaded going down steep descents in the rain. Tires are currently the stock Bontrager Hardcase 700 x 32c on stock aluminum rims.

From my searches so far, it appears that I am going to want to use Kool Stop pads with at least some Salmon compound. I understand there may be a tendency for squealing with the Salmons on the front. In the experience of those who have gone before me, does going to a dual compound pad (black/salmon) help this problem? Or, all things considered, should I go with just Salmon?

Would one recommend the MTB version of the Kool Stop (presumably larger surface area and thicker with expected longer life expectancy) even though the curvature is designed for a slightly smaller diameter wheel? Would it fit appropriately on the Trek 520 or should I go with the Thinline? Would the Thinline (less material and presumably shorter life expectancy but curvature matching the 700c rim) likely last 4200 miles or am I going to want to bring an extra set for when I hit West Virginia?

Regarding touring tires: I want to minimize the probability of flats with not only the hassle factor, but possibility of injury with a poorly timed flat. I was considering the Schwable Marathon Plus. I understand it is amongst the most punture resistant. What about expected life expectancy for this tire on this 4200 mile journey. Any comments about this being a relatively slow tire (for example, higher rolling resistance with a presumably stiffer side wall to carry the loads) or have those with touring experience found this to be a relatively easy rolling tire and therefore a good choice for the trip?

I welcome any comments and thank you in advance, Chuck