Assigning a $ Value To Vacant Land?

for example, if you’re looking at a park with 30 occupied lots and extra acreage to add another 20 lots in the future.

lets assume the city will allow this, the park is city water/sewer and the current lot rent is $175/mo

lets also assume it will cost $5,000 to run utilities to each lot

can anyone ballpark what these future lots might be worth if you were making an offer?