Nice city for sightseeing and shopping. In July you can join The Orlando Festival on July 20-31 every year.
Many students from many country will come for music competition, espeacilly the brassband competition at The Roda J.C. stadion.
Kerkrade is not very interesting. However in the immediate surroundings you have cities like Aachen, Maastricht and to less extent, Heerlen which are very much worht spending time.
Also the area of Zuid-Limburg is a pleasant area to be and spend part of your vacation. In the area there are plenty of interesting museums and other sites.