When I go out on a single day adventure, I leave this note for family/friends.
I have this form printed out on an A4 laminated sheet.
I use a fine point permanent marker to fill in the details (or cross out irrelevant details) before I head out on a trip.
I leave it in an obvious place (kitchen bench/fridge door/etc). If no one is home (or if the people at home are unreliable!) I take a photo of the page and text it to a (reliable) friend.
When I'm done, I wipe it off ready for the next trip using methylated spirits on a rag.