What’s the best way to add sky’s like this to a scene? I love the way they look. 
How do you add a separate sky image to the background or how to create the image that is the sky in your picture?
Thanks for the link Atom, also place I know how to add an image but I do need to work on positioning them better, and knowing how to create them would be nice. 
Perhaps try playing with bryce 7 whilst its FREE to download for a limited time. you just seem like the kinda person who would enjoy that kinda thing. http://www.daz3d.com/products/bryce/bryce-what-is-bryce
What is it? Sorry for the late reply.