Request for buttercream recipe.

What do you think the best buttercream frosting recipe is? I am making several dozen cupcakes for a family reunion for the 4th of July. Ideally I’d like a recipe that will travel well so I can make it ahead of time and then put on the cupcakes at the place of the party instead of traveling with frosted cupcakes for a few hours in the car. I’d like to do both vanilla and chocolate. Thanks for your help!