|The following is based on Fallout 4 cut content and has not been confirmed by canon sources.|
One room with nothing in it, with a placeholder door.
The supposed location of the interior can be deduced from the location of its mailbox, across the street from the House of Tomorrow, in front of the house with the workshop, weapons workbench and power armor station. It may have been that at some point during development, this house was to have an interior.
Rosa residence was cut from Fallout 4.