FWIW I've visited Pasha and the other 2 or 3 times, and was disappointed each time. Yes, the buildings are large, but the occupied rooms are sparse, and I didn't get a good feeling about the likely quality of experience for the ones that were there.
If in Cologne I would go here:
http://fkk-luderland.com/index.php/luderland-home.htmlIt can be easily reached by a short train ride. AO services are generally available, and it's relatively inexpensive. It's one of the RTC clubs.