If you're lucky enough to get a free and clear property where the seller is willing to finance, this reduces much of the risk associated with seller-finance.I would make sure the title is then moved over to your name, especially since there is not a risk of a due-on-sale clause being triggered.

That home was in Milpitas CA.. probably worth about 1 mil today.. but I lived there 2 years sold it made over 50k and I was off to the races.. primary home equity as I look back 50 years of ownership and multiple homes has made me well over 2.5 million in tax free gains. 

I can become a millionaire just by looking at street and sat view and bid online in my underwear. 

If I want to be free of it, I'll likely turn it over, at least for a year.

So if a competitor came to me today they probably couldn’t steal me as a client for free management.

I use Rent Redi and it is good.I also use Excel, Zelle and Zillow which are all free or I already have them.

Is the line of credit different from refinancing the home that is free and clear? 

I'd check local STR FB groups and see if you have a local Real Estate Club.You can offer your services there, maybe for free in exchange for the experience.

Please feel free to reach out if you want to learn more.

Cold calling is a great idea to get started, but maybe try connecting with local real estate groups or online forums too—they can sometimes have off-market deals.