It's not that complicated or hard, but takes nights and weekends for sure.

so I sleep well at night. 

So...let's assume you meant the former.A goal of $80k in annual cash flow is very reasonable, as long as you understand it isn't going to happen over night. 

Main house (under)rented at $1200 a night average and the casita $300 a night. 

May was $4200 because we had one 7 night and a 15 night stay!!  

If I can collaborate with someone at any point in time day or night, I personally just can't pass on any opportunity that comes my way.

String lights, fire pit, grill and some chairs go a long way and look great when lit up in night-time photos. 

Get a job working at a bar a few nights a week, buy a pressure washer and go door knocking to pressure wash driveways and decks (for example, does not have to be that), and be an agent that hustles, works open houses, goes to RE meetups, networks like crazy, and learns a lot. 

My neighbors wouldn’t like a STR and I think my location wouldn’t warrant a strong enough nightly rate. 

In my current case, guest is in town for a wedding, has been there a night, and just reached out to me today to inform me that someone in her group brought a service dog.