I want to try this recipe from CC:

http://www.cakecentral.com/cake_recipe-2019-Whipped-Cream-Buttercream-Frosting.html

but I'm wondering if it will crust enough to use the Viva smoothing method on. If not, what's the best way to smooth it?

If you add the additional Tbs of MP along with the PS, you should be fine with crusting. You also could add a little more PS. I personally have never used this icing so I'm not 100% sure. If my icing doesn't turn out enough for me to smooth with Viva, I will let it come to room temp and smooth it with my spatual.
Sorry I couldn't be more help!

i use the buttercream dream recipe, but use heavy cream instead of milk and it crusts fine.

i use the buttercream dream a lot.. using whipping cream.. pack of dream whip added. and it crust great also..

I have used this recipe. I dont think it crusts quite enough to use the viva method with it. It is a very nice textured icing though. I did not find it overly difficult to get it smooth. Tastes good too!