I take closer pictures to document a stain, scrape, or other damage.

Cat urine is extremely difficult to get out of carpeting and pads and while there are some good products out there to remove the stains and odors it is still a toss up as to whether the smell goes away forever. 

Also take a look at the grading of the surrounding ground to make sure water flows away from the house, not to the house.Siding can hide many damages, if you see patches or cheap siding recently installed, it is time to start asking , what and why.HVAC, how old, how old is the ducts, take a peak in the the registers, how dirty they are, HVAC handler closet, look for mold in this area, the condensate water drain condition and where it goes.Electrical panel model and manufacturer, google it for recalls.Floor carpet if any, I hate carpet because it hide damages and if it is secure you cant pulled it to look under, look for stains or cold spots, that is an indication of a wet spot. specially near baths Kitchen or egress doors.Kitchens and baths, old or new, try to look behind frig and dishwasher, they hide a lot of  water damages and are very subjectable for mold growth.

We had to replace some sheets where the stain wouldn't come out. 

New lighting and faucets added throughout, all wood floors were stained in gun stock, and all interior walls were repainted with a darker gray in bedrooms and a lighter gray in common areas with a bright white trim.

I would be inclined to order a deck cleaner/wash, a deck paint of your color preference, and general paint/staining supplies (brushes, rollers) from a nearby Home Depot/Lowe's, pay for them, and have them available for pick-up by the tenant at the contractor's desk. 

She called me and told me that my tenant's new boyfriend is a dirt bag, is ruining the house, there are holes in the wall and stains on the new carpet. 

On the envelope you could include personal touches like a coffee stain, stamp, a cologne spray, an ink smudge...anything to encourage her to open it.If you have no valid mailing address, you could search her name on your county's tax assessor's office to see if any other properties come up...also check ADJACENT COUNTIES' tax assessor's records. 

The iron content is at it's limit, and you'll get red stains on anything where water sits as it oxidizes with exposure to air but a water softener will take care of that.

Stain them a nice, light, neutral color.