room temp okay for cream cheese butter frosting?
Slightly different frosting, but...
I made cream cheese frosting last weekend and put it on cupcakes, and kept them it in my friend's car while we drove around Sonoma all day. By mid-afternoon when I ate a cupcake, the frosting was soft but still retaining a surprising amount of its integrity. I would assume your office is much cooler than a car, and that you'll be okay.
Also found this link on another post, which suggests substituting some of the butter with shortening to keep it from melting.
The cream cheese butter frosted cakes I've made in the past have not fared well sitting outside the fridge for more than 1-2 hours. While the shape holds for the most part, the texture of the frosting turns greasy and soggy. I think it's the butter more than the cream cheese that objects to being room temperature.
If you're putting all the work into making a homemade cake and frosting, why risk it? Maybe you can bring it in a cooler with the cake sitting on top of an ice pack. Plus, it's less likely to get pinched or have fingermarks in the frosting that way.