You can watch and read all the books in the world.

I have read David Greene's BRRRR book and countless biggerpockets posts on the topic, but recognize there are market specifics I don't yet know.

This could be an individual person willing to give you money, or a private bank, or an organization or business of some sort.The long answer is much longer and if you're interested in diving into the topic here's a few resources I can recommend:These are two great books (also available as audio books and e-books) that go over the fundamentals of what private lending are, what it means to raise capital, how to find deals to buy with private capital, and a lot more.

Some will offer 'sale prices' on inventory homes (homes that are withing 60-90 days of being complete or are complete to get them off of their books).

I recommend checking out some of the BP books such as Rental Property Investing by Brandon Turner or Buy, Rehab, Rent, Refinance, Repeat by David Greene. 

They didn't have all the real estate books, blogs, YouTube gurus, financial calculators, etc.The best thing you can do is buy a house and educate yourself on how to manage it well.

@Michael Peters Most of the answers here are good advice on pumping more frequently if you're worried, but unless you book it 90-100% of the year, it doesn't get used as much as you would think.

It sounds like you follow the teachings of Chad Carson's book, The Small and Mighty Real Estate Investor. 

Have a lawyer send the cease and desist letter, with the threat that she will be responsible for your lost rental income if she continues to harass your guests and impact your bookings. 

The book provides practical strategies for nurturing these relationships, highlighting the significance of listening, understanding, and collaborating with others.