Buying a home in the right gated community with good security (Windsor Hills is a great example) is well worth while, as well as having a strong rental agreement with guests which spells out the penalties for this type of use.

Those are two exemptions for private placements, which means its a private offering to investors. 95%+ of private capital in the U.S. is raised through Rule 506b alone.Other ways include going public (likely not what you want to do), using in intrastate offering exemption (meaning you can only have investors from that one state), Reg CF (which currently still limits you to $1M a year and needs to be done through a licensed portal, though the dollar amount is set to increase to $5M in the future), and Reg A+, which is a mini-IPO and likely too complicated for what you're trying to do.It may be possible to get ONE check from ONE investor and have it not be a security, but that depends on what jurisdiction you're in and you'd still want a lot of the same things/terms spelled out and done as you would in a securities offering to CYA--especially these days. 

@Sarah White my initial thought is any partnership should have a written agreement spelled out before starting the project.

Cash flow a new property will spell NEGATIVE CASH FLOW.

I’ve read more than enough books spelling this out in many steps, but I’m interested to see what others highlight as major “checkpoints.”

Zillow has it's moments for sure, but that 'Zestimate' is often about as accurate as the actual spelling of 'estimate'

The Operating Agreement of the property LLC will have everything spelled out. 

They generally treat the properties well, pay timely, and stay for a spell.

This could spell trouble for the market and truly prove who over payed.

It's not to say bigger partnerships can't work, but they require a lot more constant communication and I think have a lot more potential for issues.I do strongly recommend consulting an attorney to have them draw up an operating agreement for the LLC or partnership, which spells out each person's rights and responsibilities and - very importantly - how someone could leave, or be made to leave by the other people, the business.You'll need to consider questions such as, what if one person dies or becomes disabled?