Thank you so much for all your advice! THis is really eggciting for us! hahaha (my first chicken pun!) The run is going to be an "A" frame structure with hardware cloth across it so it doesn't have an open top. The coop which is attached to the back side of the run and will be a house shaped structure. I'm doing a plywood floor and the only door in is through the run. It should be fairly secure, but I think I'll still put them inside physically. I'd rather be safe then sorry, especially while they are small. We haven't built the coop yet so we're holding off on getting the chicks until the floor is all that is left to put in. I figure once we've got the chicks, we've got about 4 weeks to put the final touches on.
I'm not too worried about predators in my yard. My dogs have definitely chased off anything big. I've got 3 amazing dogs who are all very sweet with other animals. My Bulldog, Hemi will probably turn into the protector of the chicks (an upgrade from protecting my friends guinea pigs), Sasha, my oldest Pit Bull always becomes the mother to smaller animals, and Nahla my youngest Pitbull will not be allowed near the chicks. She is very sweet, but rambunctious and I can see her trying to climb the run sides. I'm putting a fence around the run as well to keep nahla from turning into a gymnast.
I'm really stoked about these new additions to our family!