Should we knock on the door of the house where Dad grew up?

On the drive towards a village outside Cork, Patrick takes a folded photograph out of his wallet. “If the door is still green, that's it. We can ask for a look round.”

His daughter Erin thought they were going to see the street where he grew up. He has not lived in the house for forty years and knows nothing about the current occupants. The photograph shows his mother beside the front step. He wants to see whether the apple tree is still in the garden.

They have arranged a driver for the afternoon, with a return time already agreed. Erin is comfortable looking from public places and visiting the village, but feels awkward arriving at a stranger's home with a request to go inside. Patrick says a polite knock lets the owner decide.

Would you suggest making contact before the day, keep the visit outside, or leave room for a brief introduction if it feels appropriate? Erin does not want to treat her father's memories as an embarrassing request, but the current residents did not book a role in their family reunion.