I am in a due diligence period on a park which cashflow-wise is a great deal.

Use a higher escrow amount and shorter DD period

If you look at a list of properties on  hudhomestore.come you will see this info under "listing period". 

I am wondering what is the most efficient and professional way to complete the tasks to get the leads.

But yours may be an area tied to issues like oil prices, so the holding period could be through a few cycles (think decade(s)).... 

This move was discovered accidentally and the comment period had only a few days left when the groups mentioned above had to frantically push other things aside to get the comments in within the commentary period. 

sounds like you are like most and need a local mentor who assists you and gets paid as a JV to your deals for x period of time.  

But what I'm struggling to understand is, once I find investors, how do I manage to pay them back, plus interest, in a relatively short time period?

@Andy Gross Also depending what type of property you invest, you could offset a higher than average vacancy rate by offering short term rental periods a la an airbnb business model when you want a higher ROI in the short term.  

It only guarantees the property free on any liens or claims during the time period in which the seller owned it.