I agree that there is little to go on, if we compare the two games directly. There are some basic shapes that could have remained such as the central lake being part of the shoreline, now.
Based on how the Eastern coastline, and Zora domain, in Breath of the wild, lines up with the Western landmass in Zelda 2, and how small the map of the original is based on its placement in the Zelda 2 map; the original game takes place in a rather small location. (Yes, I am saying that the...