I'm baking a wedding cake and will be a 4 hours drive to the wedding. The cake will be covered with sam's club whipped bettercreme. Will the bettercreme melt or will the cake messes up with a 4 hrs drive? note that weather might be in the 90-100 degrees where i'm from. I will not stack the cake until I get there.

I have taken bettercream cakes over 2 hrs away by car and as long as the sun isn't directly on it and its in air it should be fine. just do not put it in the fridge if you can help it.
It will get condensation on it, and the longer that the better cream sits at room temp the better. it gets "stiff" and will be much better on the drive.

I try to take all my cakes in one piece if possible. Have never had problems with it only the first time when i took it from fridge to car.. that was when the problem started... other wise better cream is a ver stable frosting.