This was an easy day trip and is open on Sundays if you are looking for something to do. It was about 30 min from the GK/Brunssum area and was beautifully scenic. If you have a dog that is behaved on the leash, bring “fido” along for the of nice hiking trails. Everything but the towers is dog friendly. At Drielandenpunt you can be in three countries at once by being a little creative with your body and standing in the spot where Belgium, Germany, and the Netherlands all meet . About 50 steps away, is the highest point in the Netherlands, making it a two for one trip!
There are two towers here that you can go up and view the sites and see all three countries by simply gazing around you. One tower is located in the Netherlands and was open for us to view, the other tower was in Belgium and is not open on Sundays. All of the restaurants and most of the small shops were open for Sunday.
6291 BM Vaals, Netherlands
No cost unless you go up in the towers or eat/buy something. You could bring your own picnic and it would be very nice! Parking is a few euro.
Above is the highest point in the Netherlands
looking up the NL tower