Hi @Melissa26, If you expect to list your side of the house occasionally then make a separate listing. You can show the days that are available and set the minimum number of days. After the booking you can put the listing to "sleep" and wake it up again next time you want to list your side. Potential guests will be able to see reviews/ratings for your original listing which should be good.
If you list on craigslist you will not be covered by the airbnb insurance. It is especially important to be covered if you will not be around during the booking.
Cheers, Stephanie