Would advise to proceed VERY cautiously with buying a Class D rental as your first investment.We like to think we do a pretty good job with Class C rentals, but we couldn't effectively manage Class D.The only investors we've seen "successful" with Class D are those that go by their rentals 3-4+ times/week.

I am always searching more effective systems and/or patterns.

Does anyone know if these same tools on here would be an effective resource for a commercial property analysis?

If you are doing much of anything else you are effectively brokering the sale of real property which is regulated in the US, i.e. you need a real estate license.As far as a real estate transaction goes, in brief:  get an offer accepted, enter and finish attorney review, now the property is "under contract" to sell, complete any due diligenence (e.g. inspections), get to closing...Since you are selling the Right to Purchase, you need to have a contract first. 

The owner has taken incredible care of this place - with a new roof, brand new furnaces and appliances less than 3 years ago (converted to natural gas). 

Hello Fellow Rookie,Every design is specific to how you want to effectively utilize the square area and your budget, which city are you looking at and what is your for renovation budget?

Incredible story sir.

Purchasing a primary and converting to a rental down the road is the most cost-effective way that I know of to build a real estate portfolio.

That's most cost effective way.

If it's cheaper and more cost effective to do the HELOC for that current property then stay that course because on another property you'll need 20-25% down, maybe some repairs and closing costs that you would not need for adding SF to that property you have now (that may increase your ROI for using it on the one you have now).