In this case after communicating to her the damage a eviction would be to her credit, she agreed to pay me 80% of what was owed and move out by a specified time I gave her.

Essentially the seller agrees that $X will come out of their check at closing and go to cover your closing costs at closing (debit Seller, credit buyer).

Try a local bank oR credit union first.

Do you know what your credit score is?

I agree with Zach, most loans at $20K are typically put on a credit card or borrowed from family.

Do you know what your credit score is?

act...What I like about this property: is that it has seller financing which could get me in the game sooner (without using my personal credit). 

Line of credit, cash out refi?

No you do whats called a credit bid.. you already have your money in the deal and your expenses  and tax's if you paid those.. so what ever your owed plus late fee's and interest and foreclosure costs any money paid to senior lender and insurance any property tax etc.. all that is added into your credit bid that your entitled to.. your not entitled to more though. 

Here’s the catch: The brother would be stretching to make the rent that I’m currently getting on some of the other properties I own in the neighborhood and, apparently, his credit isn’t great.