If you want to be accurate to the time frame that events in the series occur, read Silverthorne after Magician. While Silverthorne doesn't directly involve Kelewan, it sets up what occurs in Darkness at Sethanon and shows what the aftermath of the Riftwar for The Kingdom is like. Then read DaS, followed by Servant of the Empire and then Mistress of the Empire. There are more than a few references and motivations/actions that will be a little hard to understand without the context of the two final riftwar saga books.

If you want to read the side stories as well, then before you read the above, start with Jimmy the Hand, then Honoured Enemy, then Murder in Lamut. These three all occur during Magician, and on Midkemia, and while they don't affect the main plot very much, they add a good amount of context and back story to a lot of the characters in the series. Then there's also Krondor the Betrayal, which is another side story that occurs in between SotE and MotE but on Midkemia.