I was raised in the land business and sold land exclusively for many years.

@Richard Benjamin WilhiteSince you inherited the land, I believe your cost basis is typically the land's fair market value at the time of inheritance. 

Across the street is a big embankment, so no houses or land, but there are several three story apartment buildings on that next street. 

That might be a way to start, finding recently sold land on zillow, back trace agents to sold listings and tell them you might have some land coming up soon and see if they have buyers.

Answer sure.. have to check if there is a due on sale clause or if you have a PG to the orignal seller.. that mortgage stays in your name unless there is a formal assumption  Maybe the example is more challenging for a house as the property.Ex. with vacant land - seller finances to me $20k with 5% down and $1k/moCan I after 1-2 months, then resell the land to a cash buyer for $25k, pay off the original $20k and pocket the $5k?

how much land and how much money do you have?

I am a long-term investor with a buy and hold property in Brooklyn, NY and I also own multiple lands in Florida and Mississippi.

Should the bank ever need to foreclose on the property, they can’t sell the building without the land or the land without the building.

Then I would speak with a land surveyor or civil engineer to get a sense of what it would take to obtain all the entitlements and bring in the utilities, etc.     

Is it possible to keep my land loan out of it to keep the total cost low?