overbyte

I'm hoping someone with experience riding in Portland and Eugene can help me on this.

I'm planning to take a trip by bus and Amtrak train to Portland and Eugene, Oregon, in July this year. I want to explore these 2 cities, have some fun, and photograph their bike infrastructure to make a video to educate my home city and county about the things Portand especially has done to make it a safe, convenient place to ride a bike for fun and transportation. I'm going to take a side trip from Eugene out to the Oregon Country Fair, too. I want to take one of my folding bikes along, since it's easier to take a small folder than a full-size bike on Amtrak, for reasons explained in other threads.

My question is about the smallest bike I could take, which has 46 gear inches, single speed, freewheel, not a fixie. I'm not familiar with the topography of these 2 cities and the route from Eugene westward to Veneta where the Fair will be located. I know I can sit on the little bike going up a grade of 3% or less. At a cadence of 60 rpm, I travel 8 mph; at 90 rpm, 12 mph. Will I have trouble getting around on 2 wheels with this little bike? Should I bring my 16-speed folding bike which has great gear range?