From Siem Reap, you can explore Tonle Sap lake and the floating villages. Before you book a tour though, I advise you to read some of the tripadvisor reviews to adjust your expectations.
When you want to explore Cambodia, the beaten path obviously leads you to Siem Reap. The airport has very convenient connections to almost all major cities in Southeast Asia. So this is where I started my journey. To be honest I didn’t know much about the country and its history. I knew I wanted to see “the temples”. The name Angkor Wat rang a bell and I remembered pictures with temples overgrown by trees and huge stony faces.