Or do you want to put up the current loan as collateral for future purchases?

I'd suggest that you HML types out there review the changes and not assume that your loan to Frank the Flipper is exempt with 1-4 family residential properties taken as collateral.

Since you are a contractor I assume you can build a home - ever thought of building spec on privately owned vacant lots using the lot as collateral and including the owner in the upside of the property sale?  

I focus on collateral first. 

We used that Mobile property as collateral and put ZERO down.  

The Mortgage (or deed of trust in some states) is the legal instrument which secures the property as collateral for the loan.It is important to think of it in those terms as they have two different purposes.

They would secure the loan using the properties as collateral.  

I started out with buying a couple 2 Bedroom 1 Bath rent houses for 45 & 55 Grand. 20% down on each using my primary residence equity as collateral.

He wants to buy the land cash and post it as collateral as best case scenario OR land + engineering & permit costs until everything is ready to break ground (ie a day before demolition/foundation works start) as worst case scenario (say 100-150 land + approved permits). 3.

The real estate is held as collateral on the mortgage, but the individual pieces of the real estate may be sold without retiring the entire mortgage.