About two hours from Cambutal are Chitre and Las Tablas, the two closest major towns to get most modern comforts (McDonalds, big grocery stores, health food stores, etc).

We own the property outright but have a large mortgage on our own house (we combined both mortgages a few years back when interest rates were low but it will take us another 20 years to pay it off).

I'm in the process of drafting a prenup; I currently have two LLC's, with a total of five houses combined valued at roughly $900K, half of which is mine, half belonging to my business partner; I also have two rental properties held in my name. 

Get a stainless one if you don't already have it so it matches the stove.Add a dishwasher - also stainless to match.Consider demoing and replacing the tile backsplash to something more modern.

A cash-out refinance sounds better than the HELOC+mortgage combination on the first property.Item #3 looks like it can give you a very fast cash replenishment. $120k in profit, meaning you recover your equity, repay all the debt and repay whatever the cost of the rehab sounds like a great return.

I think you should start by looking at your strengths and weaknesses.If you like to fix things then flipping and landlording are the way to go.If you like numbers and aren't handy, then note investing and mortgages are the way to go.What I'm getting at is that you can amplify your success if you combine your real estate investing with something you're gifted at. 

There are like 100 different combinations out there.  

I have a couple of private investors however their lending ability combined would not meet the down payment requirement.The question I'm submitting to the forum is, how can I structure creative financing for this deal including the down payment?

If the listing is $140,000, the combined rents for the building need to be $1,400.

I plan on using a combination of strategies to get me started.