From both the A560 and the A3, you still have 30 to 45 minutes to go on (well-developed) country roads to reach Kirburg. From the A45 at Haiger, it's about 20 minutes. The signage from the road to the parking lot and from there to the ski lift is a bit inconspicuous – but it is there. There are plenty of parking spaces available, either at the "Bergstation" (paved) or at the Skihütte (gravel lot).
Access via Motorway A45 Hanau-Dortmund, exit Haiger
Roads: Highway, well-developed, without significant incline Parking spaces: enough available, tarmac car park, gravel car park, free of charge View on Google Maps
Access via Motorway A3 Frankfurt-Cologne, Dierdorf exit
Roads: Highway, well-developed, without significant incline Parking spaces: enough available, tarmac car park, gravel car park, free of charge View on Google Maps
Access via Motorway A560 Menden-Hennef, end of motorway Hennef (Sieg)
Roads: Highway, well-developed, without significant incline Parking spaces: enough available, tarmac car park, gravel car park, free of charge View on Google Maps