If it is on your taxes at the current size and that dimension is above the size that you can build without a permit (usually you can build a smaller shed without a permit) then ask if it would be okay to rebuild.   

Not to take advantage of people, but, help rebuild neighborhoods.You also may be stuck in "Analysis Paralysis ".  

If the home was ever condemned, would there be any real value in tearing it down and rebuilding on a lot I now own in a nice neighborhood, or is this being overly optimistic about taking a giant bite out of a poop sandwich?

When they need major repairs, often complete rebuilds as the mortar wears out, I just close them up, cut the chimney off below the roof and roof over it. 

They do real work, lay flooring, demo, build decks, sister framing that needs it, sometimes rebuilding the framing, lots of stuff.My first CPA said, nope, do not file the w-2s for them. 

I would consider this land in a good location and know at least 2 people who maybe interested in buying it if I could repair or rebuild it.

Invest out of state in a quad so you have a place to live during the rebuild years.

It would cost $4k, or more, to demo & rebuild new.  

If you have a recent appraisal on your property then all of that information should already be in there.A complete summary real estate appraisal on an income producing property will have three parts: Cost Approach, Sales Comparison Approach and Income Approach.The Cost Approach will tell you what it would cost to rebuild the property, less depreciation, plus the cost of the land.

Its going to require small companies that can finance homeownership to rebuild value in neighborhoods.