The house in the exterior shot of the "fixer upper" is 1619 Pine Street in Boulder, Colorado--the house used for exterior shots in "Mork & Mindy" (Mindy's apartment building).
The episode was named after 'This Old House', the long-running home improvement PBS series This Old House, originally hosted by Bob Vila.
Balki makes a comment about Suzanne Somers returning to prime time. Little did anyone know that Balki's wish would come true two seasons later when Suzanne starred in the Miller / Boyett series Step by Step. Ironically Bronson Pinchot later starred in that series in 1997.
This episode was taped on February 15, 1990.