I've seen contradicting answers to this question. I normally refrigerate my fondant covered cakes without a problem. I have a cake that will be covered in fondant with royal icing piping and around 100 royal icing rosebuds. I would prefer to store the cake in the fridge for stability purposes as i have to travel an hour to deliver it. Why does royal icing melt for some and not for others? Does the royal icing recipe make any difference? (egg whites vs meringue powder) TIA

My guess would be differing humidity.  Do you find your fondant cakes "sweat" some time after removing from the fridge as they return to room tempurature?  Where I live this does tend to happen, I think due to high humidity.  Sweating fondant would likely affect royal icing.

It varies, sometimes they sweat a bit. 

yep, I find its after its been removed from the fridge, the fondant seems to get wet and the royal icing softens