I went on a day trip from Siem Reap to 3 remote temples on one day with private car. One of those temples was Koh Ker. The site has several small and bigger stops. From the ticket booth you drive a few kilometres to the main site (with the piramide). First you enter a complex of temples and other buildings, at the end is the piramide you can climb.

After this main site you make a looping to see some small temples with lingas. On the way out many more smaller items, But also a beautifull location with 5 similar temples, two "eaten" by the trees.