Lisa, blown out skies are a problem here too and i have many pics of them lol.
The best idea is to wait for a better day, or even bracket a few shots and then merge the sky from 1 photo in with another. Or take 2 photos, 1 metered from the sky and another from the wagon and then merge them. It's a problem I know.!
I have added a different sky here using layers, erasing your sky and sliding my sky in on a lower layer.
They don't match of course but you get the idea.
I'd generally take 2 pics and see if they could be merged or better still wait for a better day.