Cycling and walking routes:
https://www.vlaanderen-fietsland.be/nl/routes/region/vlaamse-ardennen/places/geraardsbergen
https://www.wandelknooppunt.be/nl/routes/region/vlaamse-ardennen/places/geraardsbergen
...
Zoos:
Indoor and outdoor playgrounds:
http://www.uitmetkinderen.be/speeltuin/?Geraardsbergen
Do not forget to take a look at the site below, within walking distance of the house and something for everyone ..
https://oost-vlaanderen.be/ontspannen/recreatiedomeinen/de-gavers.html
You can of course also enjoy a city visit to the culture-rich Geraardsbergen and enjoy a local beer on one of the numerous terraces,
the many restaurants in the area that are happy to spoil you with their culinary arts or the numerous take-away and home-delivered meals.