I would go to city planner and ask what it would take to build, 20 Years is a long time for no one to try to buy the lot, especially in a good area, must be more to the story, After you pick up some information you will know what price to pay for the lot

This is why planners try to separate the uses.Often, you will see heavy industrial zones, with light industrial next to it.

I'm trying to get a team together of a certified financial planner, insurance agent, and also a attorney on investment relations.

A basic semester’s grounding in symbolic logic, epistemology (the study of how we know what we know), theories of causation and metaphysics will help you to get suitably skeptical the next time some financial planner claims to be able to help you predict the future (for a fee of course).Next time - the books I like.

Sometimes sellers like 1031 buyers especially the poor planners.

Sadly, most estate/financial planners are woefully ignorant of ALL the ramifications and tend to be experts in a small range.

So I would also check with your city planner to see how they could help you.

I have typically found the city planners and building department to be very helpful and friendly.

i'm a planner and admittedly sometime too much planning too far into the future.  

If you're really on the fence about it, I highly recommend speaking to a financial planner who knows real estate well, a mortgage broker who can explain what you could get out of your home without selling, and a realtor who could give you a complete view of what you will net after selling costs.