Quite a number of American descendants of the Wittgenstein Riedesels (and other families) have enjoyed traveling back there. Keep in mind that this is still a rather rural area. The principal town of Bad Berleburg has only around 5,000 residents and the surrounding villages often have fewer than 1,000. This is not Berlin or Rothenburg or the Rhineland where tourism is a huge business and English is widely spoken.
That said, I would be glad to consult with you on travel plans. I have excellent contacts in Wunderthausen and can assure you of an hospitable welcome. Feel free to contact me by email.
The town of Bad Berleburg (pictured below) maintains a website for tourists but you can understand that it is all in German. The community of Erndtebrück also has a tourist area on its website (also in German).
Where John Henry, Peter and Marie (Zehner) Riedesel came from is now part of France and no Riedesels live there any more. There are a few Riedesels in Western Pomerania (Vorpommern) around Stralsund and the island of Rügen. Unfortunately I have no contacts there.