I have already built a smaller accessory unit on the property.  

Instead of saying why things won't work for you, try to brainstorm ways you could make them work, even if it's just an intellectual exercise.If renting rooms isn't a good fit since you're a family man, how about buying a single family home with an accessory dwelling?

It's considered an accessory use to your primary residence, but when you move out -- again, technically, you're only allowed to rent the whole space to one party.)

Here is the Urban Growth Area Map.http://www.co.thurston.wa.us/planning/comp-plan/docs/M-14%20ugas%20for%20land%20use%20chapter%20gina.pdf Here is a quote from the Thurston Co. website:http://www.co.thurston.wa.us/permitting/faq/faq-aboutproperty.htm  Can I build an accessory dwelling unit or an accessory living quarters on my property?

There is an accessory dwelling unit, which I intend to rent out.

The code you cited states that accessory structures can't be rented out. 

Is it even worthwhile to build an accessory apartment? 

My wife bought several sets of furniture and accessories, each with a different color scheme.

I am beginning to think maybe some agents might consider such an accessory if they like to fly solo when doing business with strangers.

@Chad Clement Both accessory and principal require homestead exemption.