Save the final directions before the signal disappears
A saved postcode is useful, but it may not be enough to identify a rural cottage's entrance.

Save the complete arrival message
Keep the owner's final directions, property name and key instructions together before leaving. Make them available offline rather than relying on reopening an email with poor reception. If several people travel separately, share the relevant information with each driver through a suitable private channel.
Check whether the map pin is exact and whether the owner recommends a particular final approach. Rural postcodes can cover several properties, and an app may choose a route that is less convenient than the supplied directions. Resolve a disagreement between the two before travelling where possible.
Include the contact number and the stated hours or process for arrival problems. A screenshot of a message can be useful, but ensure it contains the whole instruction rather than cutting off the final paragraph or access code.
Know what you are looking for
Read the description of the entrance before the last part of the journey. A named gate, sign or building can be easier to identify when you already expect it. Ask for clarification if the instructions rely on a landmark that seems ambiguous.
Passengers can help with the saved information while the driver concentrates. If you need to reconsider the route, stop in a suitable place rather than trying to read messages while moving.
Do not enter a neighbouring drive simply because the property looks similar to the photograph. Confirm the name or contact the manager if uncertain.
Keep the details private
Arrival codes and key locations are access information, not travel content to post publicly. Share them only with the people who need them, and follow any instructions about when a code becomes valid.
Once inside, keep the return journey in mind too. Save the property location for your own use and make sure everyone knows how to find the correct entrance after an outing. Ten minutes of preparation before departure can prevent a frustrating search at the end of a long drive.