As Mike-san wrote, you might miss the address. If it's 513 Ranbashi-zaimokuza, the present address is 14-9 Zaimokuza 5chome, Kamakura-shi. Another possibility is 5-1-3 Zaimokuza (= 1-3 Zaimokuza 5chome), but this address started to be used since October 1, 1964, so I think Ranbashi-zaimokuza is more possible. Anyway, I checked the both addresses, and found that Horii family doesn't live there now (Shimazu is at the former address, and Hotta is at the latter).
From a letter:
"My father's employed in a company.
This company was founded by my great-grandfather in about 1894, the copying-presses and made by there."
As we were early teens, I would think that she would have married and, if name customs are similar to here, changed her family name.
As i read the envelope, the address is as I sent it, I could scann and send an image.....