There is a parking lot in the forest located at the base of the Mahlberg. It might be a bit challenging to find if you rely on Google Maps and approach it from the motorway towards Cologne. However, it is easier to access the parking lot if you approach it from the opposite direction.
The park area is surely a nice place to park. However, Google Maps may direct you to the wrong location when driving from the highway towards Cologne. It is recommended to approach the parking area from the opposite direction for easier access.