With the light weight barrel something like the UBR might make her a little heavy in the ass. Personally, I'd stick to something light and simple. I'm partial to the VLTOR Imod myself. Although the new Magpul SL and the BCM Gunfighter stock intrigue me.

The Daniel Defense sights are excellent for fixed iron sights.

And don't buy into Kazoo's theory. He's not getting any younger and his eye sight probably isn't what it used to be. I love fixed sights on the AR platform. As long as you can see your target, hitting it with iron sights out to about 300 yards is easy.