Getting to Mörel is very easy, at least if you live in the Netherlands. From Amsterdam there is a daily train to Bern. This international train is called Berner Oberland. As I said, you have to take the train to Bern, where you have to change trains to Brig. You have 15 minutes to do so, so that's plenty of time. I can advise you to reserve the seats, because in Germany you can get fantastic discounts (40%!!) if you buy tickets at least 14 days before departure!! Going by train is also very comfortable as you can see on the pic ;-) From Brig there is a connecting bus or train to Mörel, which leave outside the main building. This will bring you to the Riederalp Bahnen (see other 'Transportation' tip).
From Mörel there is a cable car that will bring you up to Riederalp. The cable car brings you up to Riederalp in about 7 minutes. It runs very efficient and has a good connection with the buses and the trains in Mörel.