People buy properties in non-drivable markets constantly, and in general this is what David Greene's book Long-Distance Real Estate Investing is about. 

Financing the lenders for this type of product tend to want a forward commitment lease signed by the tenant.

I am an empty nester who needed to find ways to be productive with my time.

eXp Realty is a brokerage you can look into as we're very investor-friendly and have low production requirements, however, any sponsor (and Broker) you sign under will certainly expect a minimum of 2 (non-personal) deals a year... 

I thought that a HELOC was the way to go as I am able to access the capital multiple times at any time, however, after listening to David Greene's Q&A, he said that a cash out refinance would be better.If I were to invest into commercial or multifamily real estate, a cash out refinance would be better, right?

I owner-occupy a 4-plex that I bought about 6 months ago, and I'd like to utilize some that equity, but I'm having difficulty finding any loan programs for my situation (I'm aware that this would be a unicorn product). 

🔽A drop in lumber prices has invigorated demand for commercial building projects, especially for multifamily product, Sherwood Lumber chief operating officer Kyle Little told CNBC last week.

Building a down payment and a reserve fund may prolong your time window to "be ready" to invest but it will certainly make your investment more productive and promote success.

It seems like SPC is a better choice because it will last a lot longer, and is waterproof so we can use one product throughout the homes. 

@Stephanie Wells I am a licensed lender and I do know of the product.