jason from Eureka AR on 10/31/2010 12:42:54 AM:
The best ride I ever had on the Katy was with old cheapo 27" 28MM Tires. It was dry, and in July packed down pretty hard. The few sandy sections were no problem really. I coasted a lot while fatter tires had to keep pedaling. Another trip was part of a longer tour, in 1.5" 26" tires, with a wetter trail, and I found it kind of tireing. I kept wishing that I was back on the 27" wheels.
This winter I will be tackling it with 32mm 700c tires, mostly because that is what is on my tourer right now.
This spring I plan on hitting it with a vintage path racer type bike on 25mm tires, about as thin as I would want to try. If its wet, I expect a slog on those, but I will be going for speed that trip.
Regardless of the tire, it is best to realize that conditions change a lot, and bringing lots of patches/spare tubes is a good idea.