Mary,
I think you've hit the nail on the head.  Heritage Tourism is a viable way to
enhance the economic base of cities.  As industry, agriculture or whatever
sustained a community changes or is no longer a factor...inviting the tourists
works.  If the local population "catches" the area "in time", preservation
becomes real - not a perceived or imagined reconstruction (and less costly).
The community remains living.
It is always easy for preservationists (particularly the outsiders vs the
locals) to say "save - save - you should 'uv done so and so".  The local
population also needs to understand the ramifications of lots of tourists
beyond the economic to the inconveniences (and perhaps damage) of having us
around.  These thought out, a happy medium can perhaps be found - if that is
what is wanted.  It could be that many communities don't want "medium", but
the whole shebang; and that's OK.

Another northern "snob",
Candy B