Your bike tour begins in Phnom Penh, where you'll meet your guide and receive your bike and helmet. Ride past the old, recently restored railway station, and with just few more pedal strokes, you'll be the open spaces among rice fields and villages.
Your route follows small trails and back roads where local people wave to you as you go. Reach Oudong Mountain to visit the hilltop temple of what was once the capital of Cambodia, and then enjoy a picnic lunch. The trip back to town is less strenuous, as you'll be able to rest your legs with a ride in a remorque (tuk-tuk).
If you have a reasonable level of fitness and do some occasional riding, then this bike tour should be achievable and enjoyable. The distance is roughly 37 miles (60 km) on mainly flat tracks and small roads.