We had a mini break (6 days) in this excellent hotel and really enjoyed our time there. The facilities (pool and three saunas) were great, as was the breakfast buffet. Staff were friendly and helpful.
We enjoyed roaming the village and went on a local forest walk past the Castle and two monasteries. Beautiful views.
There are many attractions close to Ilsenburg (within 30 m) which are worth visiting, e.g the UNESCO World Heritage site Quedlinburg with its 2069 medieval houses and churches, and the city of Goslar.
Wernigerode is also beautiful, and you can take a small train from there to go to the Brocken, the highest "mountain" (just over 1100 metres) in the area. We did not run out of places we wanted to see.
The area is great for hiking and it is possible to rent all sorts of bikes.