chizlit, I am so sorry! I just realised that I completely forgot to reply to your PM. Anyway, I think I can help you:
Do not take the train to Kerkrade! Instead, take the train from Aachen to Heerlen. From there you can take the bus nr. 28 directly to the zoo. It departs every 20 minutes approx. Forget about reading the Dutch bus schedules! They are written in some kind of kryptic kode from "The Matrix". The bus ride takes approx 25. minutes. The bus stop is named GaiaPark (ask the bus driver). However, you have to leave early from Cologne if you want to have enough time at GaiaPark.
BUT, I would choose NOT to visit GaiaPark late in November if I were you. GaiaPark is strichtly an outdoor attraction with a lot of tropical animals that can only be seen outdoors but not in cold weather. There are many more zoos in the Cologne-area where I think you would have a much better time late in November.
In your PM you asked me if Dortmund Zoo was worthwhile visiting. I certainly think so! Their house for anteaters, tamanduas, armadillos and sloths is not big but certainly a must-see for zoo-enthusiasts. I am not sure how many of them you have seen but in your PM you mention Cologne Zoo, Wuppertal Zoo and Duisburg Zoo, all of which are worthwhile to see again and way better suited for winter visits than GaiaPark.
Others I can recommend are Frankfurt Zoo (easily reached from Cologne with ICE or perhaps IC). I have not seen Krefeld Zoo myself but that is also a suggestion I would make as well as the Allwetterzoo Münster. If you are into reptiles that I would suggest the Aquazoo Düsseldorf.
Both Cologne, Wuppertal, Duisburg, Dortmund and Frankfurt I know for sure are better suited for that time of year, and I think it is the same with Krefeld and Allwetterzoo Münster ("Allwetter" means "all weather"

). I think that GaiaPark is a great zoo but really not suited for the colder seasons. I would save it for another and warmer time if I were you. That is just my advice
Hope this helps and sorry for the late reply!