Such hard decisions to make. In situation I think I would get started on a good strong run before I got more. It wouldn't be a bad idea to also build an additional pen for new birds. your girl should be okay for a few weeks on her own, she would have to be isolated from the other birds anyway for a time.
As far as sun, can you let her out at least once a day with you out with her? I hope everything works out.
Just some history; I live on the edge of a small community, Fairgrounds to one side an elderly neighbor to the other, with none behind us. I was free ranging my flock in an area behind their coop this summer with no problems. We finished a large run area for them now, and I still let them out occasionally during the day when I'm home! We are lucky enough to have only had one incident with a hawk (he picked up a bird I had nursed after an injury that had some genetic issues already), but after reading stories like this and many others we weren't willing to keep taking chances. Unfortunately sometimes we have to compromise even the most ideal situation for the safety of our fluffy-butts
I'm almost certain he holds a tiny grudge that *just* one hen made it, otherwise he could talk me into just quitting birds for now.. 
lol
