We spent ten days in Siem Reap, Cambodia and had a seven-day pass to the Angkor Archeological Park. The central ruins, monuments and temples are spread out in a forested and mostly shaded 10 square kilometers area with paved roads. The park is about 5 km north of Siem Reap and it was easy to rent bikes and peddle around the park. Most days were spent exploring 3-4 temples for about 5-8 hours in the majestic, peaceful, ancient, bizarre and stunning place. Slowly riding the bike in the park under the trees and then peddling up the dirt road to a massive old ruin was spectacular. Some evenings were enjoyed with an icy gin and tonic (Cambodia has some super low import tax, so good gins were cheap).
The most frequented sites are visited by big bus tour groups: They do a day trip to Angkor Wat, Ta Prom and Phnom Bakheng (avoid this place at sunset as everyone is there). Another way for most individual travelers is hiring a tuk tuk driver for either a sun rise tour (Angkor Wat west gate) leaving at 5am to 1pm, a full day tour going where they please, afternoon tour to Angkor Bayan and see the sunset (Phnom Bakheng), or the 3 other complexes that are 15 km east of town.
Each day and all day long we would be asked about hiring a tuk tuk. The tourists in Siem Reap provide a lot money to the Cambodian economy but the Cambodians are easy-going and have a nice sense of humour about it. Here is a video that gives a small glimpse of the tuk tuk culture.