Take a Christmas walk with one drawing stop
Take a scrap of paper and a pencil on a familiar short walk. Let the child choose one thing to sketch or point out; a view from your own window works too.

A Christmas walk can have one small drawing stop rather than a list of things everyone must find. Take a scrap of paper and a pencil, choose a familiar short route and let the child select something to sketch. The drawing records what caught their attention, not everything you passed on the way.
Choose the route before the drawing subject
Use a route you know and can comfortably return from. An adult checks the current conditions, daylight and suitable places to stop before setting out. Dress for the conditions; a firm backing can make drawing easier.
Agree that you will stop only where the group can stand comfortably without blocking a path or road. A decorated doorway, a familiar tree or a window seen from a public path can be enough. Do not enter someone's property or move their decorations to improve the picture. If the outing does not suit the day, choose a view from your own window instead.
Notice a detail before drawing
If the child wants a starting prompt, suggest up to three things to notice: a shape, an arrangement and a small detail, for example. One is enough. They might choose the outline of a door, a wreath in its center and one broad ribbon. Words or pointing can replace drawing if that is what they prefer.
Begin with the largest shape and add any details the child wants. Here is a proposed example: a rectangle becomes the doorway, a circle the wreath and two short loops the bow. The picture need not copy every leaf or ornament. Stop the sketch when the child has recorded their chosen details, or sooner if they want to move on.
Let the walk continue after the sketch
Put the pencil and sheet away before walking again. You can talk about another sight without making another stop. One drawing is a complete version of this activity; it does not create an obligation to finish a collection.
At home, let the maker explain the drawing or add to it if wanted. A window sketch can have the same ending, without needing to turn the day into an outing after all.
