Or is it better to capture all the rental income while continuing to pay my current rent at $500/month?

It can be a simple one page contract b/w you too at an agreed upon rate.

I know I can go through a lawyer but I was told it is a fairly simple process hence want to DIY.Regards,Xuming

Plain and simple, knows his stuff.

Your mentor has needs; try to meet them and develop a mutually beneficial relationship.A mentor can benefit your growth, but it's not as simple as one post on a forum full of strangers.

Here is an article i found with a simple google search: about $5000 but i thought quiet title in georgia was actually higher.Tax Deed Services For Owners of Tax Deeds - Gomez & Golomb LLC

It could be something as simple as a toilet running. 

Do plenty of research and find out what other mistakes have been made in your are and learn from them.Both are great options but maybe doing a simple pros/cons list for both STR and LTR.

It's simple really.  

You can secure the property with a promissory note drafted by a lawyer or a title company, but keep in mind that “taking back the property with the note” as it is often pitched by gurus is not always actually that simple.