So I read on here a thread from 3 years ago (eek!) about this amazing whipped frosting that was heavy whipping cream and pudding mix.

YUM! Probably the best whipped icing I have ever had! LOVE IT!

ANYWAY - I just made a batch about an hour ago because I have a request for a whipped frosting. (I have hated the taste of everything I have tried thus far.) It piped great, had a nice texture... I have some piped details sitting out to see what happens with time and temperature.

My questions are - because I know some of you guys have used this recipe before - how long can it stay out at room temperature (like during a several-hour party)? Will it hold up? How many days will it stay edible? I know it needs to be refrigerated because of the cream and all. But will they be able to keep the cake for a couple days? A week?

I want to make the frosting on Thursday, pipe and decorate on Friday, and then their party is Saturday. They are an hour away as well, so drive-time needs to be included in the staying-out-at-room-temp time.

Any help and past experience would be GREATLY appreciated! :-)

Cakes with this stuff need to be stored in the fridge whenever possible.  A well chilled cake can sit at room temperature for about 3 hours before it starts to get warm up in the middle.

I think you would be far better off baking cake a few days ahead(frozen cake layers would be just fine). Make the topping  up the evening before the party and immediately ice the layers and chill them.  Make up a fresh batch to decorate with in the morning.

That way you can drive for an hour starting with dead cold cake in a picnic cooler and ice packs.  The party plus leftovers will then be as safe as humanly possible from your side of the timeline.  Make up a few printed sheets with "CHILL CAKE" warnings for after the party...