Well,
I received my BS in Historic Preservation in Dec 1995 and still am not in
the field.  Now I have a steady job in another field, but still have hopes
to enter the HP field with just a BS degree.  I have found this might be
possible if you are willing to do some major volunteer work first or are a
real go-getter and can convince a historical assoc to fund you (or sponsor
you as you apply for grant/funding yourself)

Mike Highfield