Hello @Mark Ellis
Any of the options discussed (turnkey, private notes, and crowdfunding) have their own set of benefits and risks.
Turnkey, although promoted as completely passive, still requires more input from the investor than notes or crowdfunding.
Notes and crowdfunding are very similar but while crowdfunding is easily accessible and can often be completed online, notes generally require quite a bit of networking on the part of the investor. I personally prefer crowdfunding because it's more flexible and can easily be conducted virtually but I'm obviously biased due to my previous experience with crowdfunding. :)
@Larry Fried brought up a really great point. No matter which strategy you decide to pursue, the quality of the sponsor (operator) actually carrying out the project is one of the most important factors. Look at their track record, Google them to see what others are saying, and do some research yourself to see if their claims match the market conditions.
Feel free to reach out if you'd like to discuss further or if I can answer any additional questions.