If you prefer to maintain liquidity and have the potential to handle multiple projects, HML might be the way to go. 

Cool.

I've purchased for that amount and they turned out to be good notes.I liquidated my RothIRA for a SDIRA Roth account in order to invest and continue to contribute.

I don't make my clients sign long term contract either just per a property saying will pay me the difference if we don't get at least 2.5% and everyone been cool with it. 

If you prefer more liquidity, using cash flow to build savings may be a prudent choice.

So I analyse each property individually, looking at major features like roof, heating, cooling, hot water, anything likely to break down really. 

If you decide to entertain this, due diligence will involve digging deep into the business financials to understand cashflow, solvency, and liquidity, his personal finances, and searching for any liens or UCCs in place. 

I have no idea what the outside temperatures are (ie it is really hot out or cooler) and is she doing things to help keep the house cool? 

I was wondering if I am in this situation again, can I pay cash (I have the liquidity) and then refinance after closing?

I'm leaning more towards flips for my first few deals just to help create more liquid cash in my account.