Professor at Hochschule Düsseldorf
Theoretically, yes. But you must start early in your lifetime.
If you do not have to work and if you do not have other obligations and if you have ample funds you might be able to visit 2 castles per day. If you do this on 200 days per year - excluding some time for resting on weekends, for illness and for vacation - you might visit 400 castles per year.
If you maintain your speed you will have visited all 25,000 castles in Germany after 63 years. This means, you should not be older than 20 when you start with your task. And you should be the heir of a billionaire. And you should not have any other interest.
Good luck!
