I have been told a metal band across the from with angle iron on the building corner tied off to the side parapet walls that step down might be best. 

Lastly, I started doing this with all of my crews but each person on site must sign a hold harmless agreement that they are responsible for insuring their own bodily harm and are responsibly for caring their own insurance. 

I have replaced many of the runs--largely the copper is at end of useful life, but also I have some electrolysis where an earlier owner hung the copper with a dis-similar metal and there is heavy corrosion.I also insulated all pipes and ventilate well in summer, cover vents for freeze months.And I had the PEX bid, two... but have not tackled it just yet...

Metal theives would be aware if your state has that law and will probably leave it alone.  

We are building an addition, refacing the exterior with limestone, changing the roofline and installing a metal roof, replacing concrete, new landscape and resurfacing the parking lot. 

Another option is to dress up the metal railings with a wood cap that you can stain.

Market rate would be about $1600-$2,000 depending on condition.  2nd floor is old and run down looking, but overall ok.  2nd floor has an enclosed porch that is supported on metal beams but looks like it needs to be totally fixed, peeling paint, torn screens, rotting floor boards. 

In general, these are going to be the extremes ($60 per square through $200 per square).So, if you add materials and labor, you're likely talking between $150 and $300 per square for a licensed/insured contractor who is accustomed to working with investors.Of course, if you want a different type of roof (metal, aluminum, clay, rubber, etc), or if the roof is complex/steep, or if the roof is really high, you'll definitely see variations from that range.

If most houses in that price range have some sort of premium roof (metal, slate, whatever), then I agree the 3 tab shingle will cheapen the house and make it less competitive. 

However, it is a combination roof on a house that had an addition - the original roof is metal shingled, the addition is asphalt shingles.