You must possess an admission pass (an ‘Angkor Pass’) to visit the temples and sites in the Angkor Archaeological Park. Passes may be purchased at the main entrance on the road to Angkor Wat. Passes are sold in one-day ($37), three-day ($62), and seven-day ($72) blocks that must be used on consecutive days.

To get around Angkor Wat you need a vehicle, no way you can walk the whole complex. Foreigners are not allowed to drive inside the park, so you must hire a bicycle, a tuk-tuk, or a van driver.  For a bicycle adventure you definitely need two or three days in the park, otherwise is impossible to see everything.