Having access to the folks that own the 22 building portfolio and learning how they raised the money for the portfolio; potentially meeting their investors and learning or their bankers... 

@Tom ServerAdding it over existing subfloor will require you to undercut all your doors, and cause havoc throughout the unitYou should replace it as it’s mentioned.Depending on the square footage of the unit not sure if 5k will be enough and assume unit is completely empty of personal belongings and has no flooring in the unit over the subfloor

Because of that I am probably going to be focused more on flips for the next 2 years to show the banks 2 years of steady income since the financing I would use for flips would have more lenient lending requirements

Many states require hard money lenders to be licensed as well.

If you want letters from previous landlords if they can meet your stated income and credit score requirements then, you also state that up front, exactly what you want.And your realtor and attorney should be helping guide you this way. 

Most lenders require you to have 6 month seasoning to do a cash-out, but I do know of an option that cuts the seasoning period down to 3 months.

Most of the older folks in the area who hold the land are approached constantly by developers so a small family looking to do what they did 30 years ago might tug at their heart strings.

My father wants to use his SDIRA to provide a loan to the LLC him and I are equal partners in.The loan would provide the additional funds we require to purchase an investment property.The LLC would pay principle and interest at market rate to the SDIRA.Would this be considered a disqualified transaction? 

Conversely, refinancing preserves your current positive cash flow and requires less hands-on work, but you may not secure the same low interest rate and could diminish the equity available for your next house hack.

Are you looking at buying/building a private strip and expanding the hangar capacity or would this be an off airport storage requiring wing removal and towing?