I like the sound of journeyed, but I guess that does sound a little too fancy.
What you could always do is also change out the “to” before “Mustafar” for more freedom of vocabulary. Example: “Meanwhile, Supreme Leader Kylo Ren has arrived on Mustafar”.
Here’s the exact definition of arrived from Google: “reach a place at the end of a journey or a stage in a journey.”
+1 to either idea.