I have a 15B that is used mostly by my adult kids. As mentioned above, the 15B is configured to sleep two by converting the dinette table into a bed. It would be possible for a third person to sleep on a pad on the floor. That is easily doable, but would definitely block access into the bathroom. I have toyed with the idea of a fairly simple mod that could allow setup of a third sleeping spot for a child on an elevated bunk along the wall on the rear drivers side of the trailer, but as of yet am grandchildless and have no current motivation to do such a thing. Possibly in a couple of years.
2013 19' \ 2013 15B, 2020 Toyota 4Runner TRD Offroad
"It is better to remain silent at the risk of being thought a fool, than to talk and remove all doubt of it." - 1907, Maurice Switzer