Welcome!
I'm confident that the Jamis will serve you well. The main factor is your comfort and you have addressed that already. As far as 18 speeds being enough...3 speeds is enough as long as the range between low and high is sufficient. I'm a firm believer that gear range is more important than number of gears, but that is just my opinion.
I ride single speed, three speed, five speed, 10 speed, 15 speed, 18 speed, 21 speed, 24 speed, and 27 speed bikes all in the same geographic area. The more gears I have means smaller jumps between gears but has no negetive effect on my ability to get where I'm going.
Oh, it may be possible to pop a rear rack on the bike with some after market adapters. I've done it with a few of my bikes.
Anxiously awaiting rides reports and pictures.
Last edited by cranky old dude; 01-24-11 at 07:50 PM.