To value a property you need to look at the market analysis and construction approach (building it today less physical depreciation/depletion).

When I do get some in the slum areas I am planning on keeping my standards high in hopes that I can help clean up that area of town.

Just clean up unused poison when your done using so the neighbor cat doesnt wander over and eat it after.

Make sure there is no eminent domain proceeding, epa cleanup issues, or pending litigation etc. that would affect the property.

But, if I understand you correctly you are just looking to have the finish work done, I am not sure what that would run you.Unfortunately, not too many people are looking to clean up your mess and give you a good deal.

Losing that tenant might leave you with a big cleanup bill.

Even if you can get rid of someone, with the law on your side, experience shows, it does pay to be decent with a resident of your investment property.Just a little civility, could save you thousands in plumbing, electrical, and fire and water cleanup and vacancy costs.......

In addition to scope of work you should walk them thru your expectations, job site clean up, safety, handling materials, assisting in take offs if needed, recommendations, work hours, crew size, duration, schedule, payment, payment process, warranty, equipment operation, etc... 

Clean up the park (odds and ends / landscaping).

My tenants do their own schedule and clean up.