These, in my opinion, are the important issues:
Comfort. Comfort is right at the top of my goals. We can quantify the number of bags of groceries but I don't know how to quantify "comfort". A tail enhances economy. But with the tail, it is awkward to throw your leg over to get on. A "Step thru" frame makes it easy... and comfortable to get on and off. A horizontal cylinder arrangement allows the engine to be under the seat... which allows a low seat. These are all a part of "comfort."
Various routes:
Vetter Challenges are held on real roads around the US, the way we really ride. It turns out that there are great differences the way we really ride around the country. The Mid Ohio Summer ride was easy. The wet roads might have troubled novice riders. Had it been a downpour, I would have cancelled and rescheduled the ride. (I really don't like to ride in downpours.) The Fall Las Vegas to Barstow ride is very different. Much higher speeds over two mountain passes, with unpredictable winds. Maybe rain. Maybe snow. But it is the way thousands run back and froth to LA every weekend. I represents the way we really drive. If it was too awful, I would not hesitate to reschedule that ride, either.
Which brings up engine size: We already know that a liquid cooled 250 - about 16 hp - is adequate for the Las Vegas to Barstow Challenge. At Ohio, Ben Schloop's air cooled 185 proved it had the power for Ohio and sipped fuel to place 2nd. But would it be able to handle the conditions of Las Vegas to Barstow?
I don't think so. It might be a very expensive venture for Ben to try to find out.
What size then? My Helix may be at the minimum of the power needed. But these Vetter Challenges have proven to be very hard on it. Alan and Vic's 250 Ninjas seem to be able to run back and forth the US with no problems.
Maybe the best solution would be to put a Ninja 250 in a special-made scooter frame and live with a seat that allows the cylinder head to protrude between your legs. With a heat shield, of course.
More later...
Craig