Love the added security of the rocks around the pen plus it looks nice. The chicks might appreciate some step cleats on the ramp about 4 inches apart. They may not need the steps as youngsters but as chickens age, get arthritic, or injured, the steps will get used. We didn't paint our ramp when we made it but just sanded the corners and splinters off so there was still natural wood for our chickens to walk on. If you paint your ramp, to keep it from being slippery add sand to the paint for traction.
What kind of cover do you plan for the run? Bird netting will be useless and sags even in a small area (it's useless over our vegetable garden). However it's better than nothing until a stronger solution can be afforded.