Originally Posted by
timdow
Durability/puncture resistance and weight are opposing characteristics.
I personally would go with Marathon Plus'es, or Marathon Tour in 38c or 40c, but I vastly favor puncture resistance and long tread wear over lower weight.
GAP and C&O, there is not a lot there to cause punctures. Pittsburgh and DC are probably the most hazardous places for flats. You can do that if you prefer, but I would not use the "plus" version on any Schwalbe tires there, but then I have never used their plus tires anywhere.