So who has some old houses?
My house in Massachusetts was built in 1783.

In the 50's and 60's my grandmother owned a house in central Brooklyn, New York, in what is now known as "Victorian Brooklyn".  I believe they were built about a hundred years ago in the area south of Prospect Park.  Each was 2.5 or 3 stories and unique in design.  Several right on her block have been converted to bed & breakfast places. 

From what I have seen on Google, most look like they are in their original form and structure.  My grandmother's house, however, was rebuilt, at least on the outside, but the front door and frame were kept intact.  That particular house is now worth about $900k. 

Some houses in that district have been designated as historical, possibly many houses , maybe even the entire area.  All the houses are well maintained.