I've been asked (last minute) to make a simple 3 tier (10", 8", 4")  wedding cake for next Saturday. I'm not worried about the decorating aspect  but I'm worried about transporting a cake with "soft" icing. Any tips would REALLY be appreciated!!! I normally use all butter ABC so I don't have much experience with this. Any tips on filling, doweling etc?! How well does this hold up? (It's not hot here now. The high for Saturday is around 50 degrees)

You do know that whipped cream icing/filling MUST be kept refrigerated at ALL times?  Have you informed your client/family?   Have you considered using the white balsamic vinegar recipe instead?   Hopefully K8 will jump in here w/a link for you as I could not find it :(      Other than that I would treat it exactly the same as I do a b'cream cake :)   BUT.......maybe drive a bit slower/carefully :) 

if you use all butter swiss meringue and keep it cold it will not be soft until it gets room temp — and keeping it boxed for delivery will keep it cold en route — 

this is the recipe lynne mentioned but it’s not whipped:

https://www.cakecentral.com/recipe/61811/white-balsamic-american-buttercream

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