I make millions annually transacting as a principal broker and owner of my company with clients.I also run a lean operation with employees extracting the most performance per worker.Many big companies tend to hire the crap out of every position having 30,40,50 people in the hopes they keep scaling.

Be very careful and have a principal that knows what he is doing.

I'm not exactly sure what this means but I think it means that your monthly principal and interest don't factor into the equation.

If you have a mortgage, it'll get a bit tricky to enter the data (principal, interest, and escrow.)

Do I just take my principal and interest and walk away?

You will then have a few options with that rent money....you can put it into principal or you can start saving it to purchase yet another property.

We have around $300k in principal left, and I was thinking about a cash out refinance. 

Thanks  Pros:-Lower monthly payment = higher cash flows-Save more equity than paying down principal, can be utilized in other projects and to scale-Generally better for tax purposes (no tax benefit to paying down principal)Cons:-Higher rate-Higher risk (deleveraging over time give you more LTV cushion generally)-Less cash out / harder to refi in the future (UPB will be higher)

My goal: create an interest-free loan which is appealing to a potential homebuyer, yet doesn't make too big of a discount on my end.For example: If I sold my $300,000 house with 20% down ($60,000) over 30 years, at 6.7% interest rate: $1548.67 principal and interest per month1548.67 x 12 x 30 = $557,521.20What I would do would offer a lower monthly payment and no usury, but it would effectively be like a prepayment penalty.Arbitrarily, let's say 20% off the monthly payment, or $309.73 less per month: $1238.94 monthly payment.House would be sold at $446,018.40, which is $111,502.8 less than the total paid with a normal mortgage, but $116,018 more than the market price.

You will then have a few options with that rent money....you can put it into principal or you can start saving it to purchase yet another property.