One of my regular riding partners and I started on the trail in Dewitt, NY yesterday (eastern Syracuse) and headed eastward. The trail started as smooth paved surface, then after a few miles turned to the crushed limestone. My guesstimate is that riding the limestone - where it was nice and wide and flat and well packed - probably robbed a couple mph off of our speed at the beginning of our ride for the same perceived effort. So maintaining about 18mph on the limestone felt like 20 on the road.
As we progressed further eastward we encountered sections where the nice limestone path became narrow sets of double track with grass between, or narrow single track less than a foot wide, or mud-covered, or looser limestone, or the pathway had branches encroaching, etc etc. All things that obviously slowed us down. We also did lose the route in a few locations where it went onto roads, or where other paths connected. For want of a few well placed arrows we rode a couple extra miles by the time we got to Utica.
We'd considered doing a double century out and back. But at Utica, with about 64 miles on the bike and the wind blowing steadily from N/NW (the direction we had to ride back into) we decided to turn. The wind hurt us going back pretty bad, and the decision to turn early was a good one. We finished with 123 miles, at an average riding speed (excluding several stops) of 16mph. I think before the turn back into the wind our moving average was between 17 and 18.
So that idea - riding 360 in 24 hrs - has been laid to rest. We both agreed that doing it in a three day / two night trip would be very enjoyable though, and plan to do that next year.
One of the strange parts for me was riding such a flat route...you never get to coast!!
Anyway - thanks for the input and thoughts, all of which proved accurate.