I am 60 years old and lived in Dover from 1947-64. I lived in Durham from 1964-77 and continued to closely follow what was happening in Dover.
The Sawyer mansion was the home of the Sawyer family, which owned the Sawyer Mills, and was one of the most elaborate houses in town. The story I heard was that he was driving thru Dover, saw the house, liked it, and bought it. I also heard that nobody lived in the house while he and his mother owned it and therefore it was hard to protect it from vandalism. It was continually vandalized thru the mid 20th century and by the mid 1950s it was considered to be beyond repair.
They did NOT tear down the house to accommodate the turnpike. In fact, when they built the turnpike in the mid 1950s, they built the ramps around the house so that the house and most of the grounds could be preserved. They tore down the house because it was an eyesore and beyond repair.
The house also had beautiful grounds, with lots of fine trees. Since the city already owned the property, the logical thing would have been to convert it to a park. It didn't happen. The property was a prime location for an eatery catering to tourists. In the mid-1960s, the city (or the owner, I am not 100% sure the city owned it then) sold the property to a developer, who cut down all the trees and built a Howard Johnson's restaurant. In the 1970s, I think, they converted it to a Burger King. So the present-day Burger King isn't just near the site of the house, it is ON the site of the house.

3  out of 3 found this valuable. Do you find this valuable? Do you?