It doesn't take long to realize that bikes have awesome access around Koln. We rolled out of the airport and onto a bike path!
The numerous bridges that cross the Rhine all had great bike paths separate from traffic.
When we got to "Neumarkt" (new downtown) I stopped at Meyerische, a large bookstore chain. The bike map department was huge! You could get bike maps for almost anywhere within 500 miles. I picked up some Bikeline maps and we did a little sight seeing.
To end the day we stayed in one of the two fine camps located just south of downtown on the Rhine. Most campgrounds include showers, washing machines, and a store/restaurant. It really isn't roughing it. These camps are right in the city and are amazingly safe.