I had to grade and level the entire property and plant new grass and it's now one of the prettiest lawns on the entire black.

For some the psychology of having no loan works - they still have the property tax (which is artificially low from Proposition 13) and insurance payments (which is increasing from wildfire risks and some major companies not taking on any new clients). 

People think history determines the future or create an artificial two way on how the future will play out--not sure why or what or where that comes into play.

Consider all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

Is there an alley way behind, large main driveway, street parking (if so, do the Adu occupants need to walk through the main house lawn?).

Like Michael said, I would use a cleaner once a month to clean or biweekly, restock the common area items (like TP, dish soap, etc), and sign up for routine lawn and snow services.

I would expect to see property management, admin, marketing, and contract services (more than just lawn care.) 

I can do all the basic things like lawn maintenance, snow removal, painting etc, and some electrical and plumbing.

How did you fund the ongoing maintenance needed for the lawn?

If after adding the additional monthly recurring costs (electricity, gas, water, internet, insurance, lawn care, snow plowing, etc.) to the standard long-term costs (Mortgage, taxes, regular insurance, etc.) the property won't net at least $100 if I can get the average rent I see on FF for that area, then the property isn't worth more investigation.