The nature park “Hohes Venn - Eifel” in Germany offers beautiful nature and a lot of space to escape from the rural environment.
Moreover, in case you want to spend 1-2 nights out in the forest without camping wild, you can easily have a look at the nice spots the trekking-eifel.de folks offer here. We spent some time at the “Ich bin mal kurz weg” and the “Land in Sicht” spot. A “ticket” can be easily ordered online - afterwards you get the GPS coordinates via email.