As far as paying down the principle, I don't think that is the best use of capital.

I'm very debt aversive, so for me I'm leaning towards paying down that mortgage just to get it to the 1/2 point on the amortization and then the monthly payments will hack away at the principle more than pay the bank interest.  

Its really not that bad when you consider that your principle payment will also be around $200 monthly.

Do you have one or two key principles that you live by that might help my as an investor?

That would be for an interest only loan where you don't pay down the principle.

The investors who are successful treat real estate investing as a business and understand the application of business principles to  real estate.

I know Wells offers a HELOC that grows annually as values increase and principle decreases. 4% ish is cheap money man.

Would it be a good decision to use the same principle when performing due diligence in financing it perhaps again with a line of credit?

I also have a finance degree which can be put to use with investing principles.

I like how the books are laid out.5) after you do the above, then locate a perspective property, apply the principles you learned, input the numbers into the tools, then come back and share your thought process, all the numbers, why you think its a good deal or not, etc.slow down to speed up.