I love to use rolled buttercream on cookies, and I need to ship some this week, but with the heat of summer, will it melt? I'm shipping them overnight, but I'm afraid the crisco base of the icing won't hold up. My other option is to use RI, but then I lose the flavor of the buttercream. Can anyone help???

Does anyone know??

I wouldn't, but I've not tried it. You could sit one in a box outside for a day & see if it melts (b/c this is practically what it'll go through). If it does you could always use butter flavoring for your RI.

Yes, it'll definitely melt! The humidity alone would kill the buttercream. I ship out chocolates, buttercream & cream cheese iced cupcakes, and cookies during these hot summer months, and I ship with insulated box liners and ice packs (tons of them when shipping chocolate). Before I got the box liners, I went to Publix (Walmart has these as well) and got one of those insulated bags that you use to keep frozen food from melting (in the freezer aisle). I then would pack everything in one of those bags with a couple of ice packs depending on the size of the box I was using and the items inside. It worked like a charm for 2 day Priority Mail! HTH!