Id go right into looking at local credit unions and small community banks for HELOCs (lines of credit) so you can have a lower blended rate and draw/payback as you please.For the 3F - Since this is free and clear, you would only be looking at 1st position options here in the world of financing.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

If you are very conservative purchase a fixer upper so you can force equity and hopefully have a low enough payment so that you can LTR the property or even sell for profit should the STR avenue not work. 

Either way if you personally guaranteed the note, yes it will affect your personal credit no matter who the property is titled to.

So I get this referral from a relative about a tenant who has good credit score, no criminal history, and a good paying job.

I own a 200 year old house that has a very low cost of repairs and maintenance over the 4 years I've owned it.

I made a low offer and it was accepted.

I have purchased the following books:ABCs of Buying Rental Property The ABCs of Property Management The ABCs of Real Estate Investing The Advanced Guide to Real Estate InvestingThe Book on Investing in Real Estate with No (and Low) Money DownWhat order do you recommend reading them in?

I have also have saved almost $50K so far to take a start in this game and also my personal credit score is above 750.I'd like someone to guide me purchasing my first property and want to kickstart with a small property first.

I know the area like the back of my hand and believe Indiana has tons of upside to invest in.I came from a low-middle-class family of teachers.