., are you keeping the plumbing configuration the same and replacing with new fixtures or will the plumbing need to be moved around? 

Giving you the stability of a long term rental with the higher, but sometimes seasonal, returns of shorter term rentals.Making sure they do not configure the house in a way that would limit them from renting it out to only one type of strategy is also a consideration.

That is especially true if it is configured in a way to add a pullout to sleep another 1-2 people.

They configured the back of the house to be a 2/1 attached ADU of about 750 sqft.

Because of that feature limitation, I ended up swapping them out for dumb irrigation controllers.As an experiment, one time I tried leaving a pre-configured wireless access point with a tenant specifically for smart smoke detectors and irrigation controller, but the tenant objected because it meant I could potentially access their network whenever I wanted, which was theoretically true (not that I would do it).

More than that, I have focussed on devices and systems that can work together for a cohesive "Smart Home" system, as well as being easy to use and configure for the buyer.

What are the unit configurations like?

There are parking requirements, but I think I'm exempt because of location < 1/2 mile from BART.Any thoughts on ideal size / configuration? 

This is essentially an IRA like any other as far as tax purposes, simply configured differently so that it can be invested into assets beyond just stocks such as real estate, private mortgages, etc.There is much information here on BP on the topic, and many of us who provide such plans.

@Richard J Reid thanks for that ☝ Could you estimate how much, percentage-wise, having this configuration adds to your expenses?