:iagree: :iagree:
Also, won't there be bees and flies? I can't help picturing a bunch of sticky, sugary kids running madly away from bees. (I'm not a big fan of eating outdoors)
My local grocery store's bakery section sells their cupcakes frozen. I've bought the mini size on the way to an event and they've been fine.
I think anything but whipped cream could freeze well.
If you really must add the frosting onsite, I would bring it in the cooler already in a piping bag (or ziploc with the corner cut off) and quickly pipe the frosting on myself. (While someone stands guard for bees of course. :D )