If there is rot and its a more extensive of a job than merely replacing the window that will drive cost as well so you should seek a line item budget from the installers.  

Try to find ideal markets that offer upside while still being at a more affordable price point than southern California for example.A few good examples are Columbus Ohio and San Antonio Texas, although you'll have to find particular neighborhoods and micro-neighborhoods to consider in whichever market you are looking at.

When the tenants moved out, he discovered they had utterly trashed the place and the cost to bring it back to market standard (and thereby get a more desirable tenant) was beyond him. 

Did you go with an LLC right when starting out or was there a more appropriate transition point say one or two years later? 

If it's your first groundup, I would definitely find a more experienced partner that you can learn from.

As a concerned neighbor we are desperate to find a more qualified owner to improve the living conditions for these residents and avert any pending disaster.

Then you can read a more in-depth book like The Book On Rental Property Investing by Brandon Turner or The Unofficial Guide to Real Estate Investing by Spencer Strauss.2.

Now I use a more sophisticated tool that provides me all the tax sale lists nation wide and reduces drastically my research time. if anyone wants to check it out: www.fastlien.co 

A more likely scenario is you will be a landlord with a tenant, and you will be responsible for the upkeep on the rental as well as your own unit Then when your renter moves out or you evict the renter for non payment of rent you will need to pay to have the unit turned unless you can do this type of work yourself.

For me, when I get home I may do a more detailed reply via my laptop.