We would like to create a partnership where we are 50/50 partners and he brings the cash and I bring the experience, knowledge, and contacts ect.

The letter stated it was a cash deal up to $300,000 which is why the decision to close in 15 days was implemented.

Eventually she just sold the contract for $50k cash (all profit to her) when the RV park sold.  

That kind backs out to 12-15% cash on cash return. 

Apparently they take preferred interest in your company or have you sign a UCC cash flow agreement.

The 4-plex would produce around $1000/mo cash flow after financing, and that financing would recover your total build cost leaving you with no money in the deal at the end and an "infinite return" for CoC.

For example, say it were a 2bd/1ba property, I would just list it for 1 nurse to stay and I would hit my cash flow goal.

Quote from @Carson Hyland: Even if you buy the right property, failing to manage it well will kill your cash flow. 

Whether this is a single family or duplex/multi-unit will depend on how much cash you have, how much work you want to do, how capable you are, etc.

Lenders want to see income, not negative cash flow, even if the loss is just on paper from depreciation.