Renting a standalone guestroom as an MTR?

[Julian Martinez]

Hey BP community, I'm spinning my wheels on the best approach here and could use the community's advice on how to approach this. 

We have a separate building on our property, which we've converted into 2 units- 1) a fully permitted ADU, and 2) a rec room, playroom, or rompus room, essentially a 450 sq ft guestroom with ensuite bath.

The ADU is listed for long term rent, that one is very cut and dry. The rec room, how would you approach it? Could it be rented as an MTR since it's essentially another bedroom, just not IN our primary residence? Or would you just promote it as a "room for rent", and then when prospective guests arrive, they see that it's essentially their own studio? (Obviously, positioning it as a "room for rent" will come with a lower price tag since folks would be expecting a private room, not a private unit.)

Eventually we will pursue full conversion of the rec room into its own unit through SB9, but that will take quite a bit more time and money. In the meantime, the plan is to use it as an MTR while we work through the SB9 process. 

Is there another approach you would suggest? It's a unique situation that I'm struggling to even find comps for when researching, so any advice would be so appreciated!