New Development South of Atlanta

[Guillermo Nadal]

I have 5 acres under contract in a city below Atlanta. Im looking to develop the land and built between 80-100 units depending of building stories. Im looking for mentors or guidance from people with experince in this area. I already paid am engineer for a concept plan and go to the city to change the zoning. But im debating in how much money I will have to spend before knowing if this deal will work for me or no. Engineer is telling meI need 15-20k spend to have an idea of how much the land development will cost. I have the builder and all the sub contractors the project will need. This is my first deal of that size and will like some advice. 

Thanks.