Pack one bag for your dog's everyday things
A compact, familiar collection is easier to use than a boot full of pet accessories. Pack around the routines your dog already has.
Keep the first few items together
Put the lead, waste bags, water bowl and towel in an accessible pocket. These are the things you may need before the cottage is fully unpacked. Keep the food container upright and separate from items that must stay dry. A bag with a washable base is useful, but any suitable bag you can recognise quickly will do; there is no need to buy a special holiday set.
Pack enough of the usual food for the stay, with a sensible allowance for a delayed journey or changed departure. Keep preparation instructions and any established care routine available to everyone responsible for the dog. If medication is involved, follow the vet's instructions for transport and storage rather than guessing what an unfamiliar cottage can provide. Check essential facilities with the host beforehand.
Make a distinction between the bag for the stay and the things needed during the journey. You should not have to lift bedding and food containers out at a stop to reach water or waste bags. A small accessible pouch can travel inside the larger bag, then remain near the cottage entrance once you arrive. This keeps the same essentials together without requiring two complete sets.
Bring the things that earn their space
Familiar bedding, a few normally used toys and your own dog towels cover more situations than several new gadgets. Include a spare lead if you already have one that is suitable. Leave bulky accessories behind when they serve no clear purpose. Consider where the bag will live in a small kitchen or hallway so that its contents can be reached without tipping everything onto the floor.
Separate clean kit from wet or dirty items on the way home. An empty washable bag inside the main bag is often enough. Do not seal damp bedding away for longer than necessary, and avoid using the cottage's household laundry baskets for muddy dog equipment unless the host has said they are intended for it.
Leave yourself a short return-home check
Before departure, look beneath the table, beside the bed and around the outside tap. Bowls and leads tend to migrate during a stay. Check your packing list against these everyday places rather than unpacking the entire bag for a count. Put the items needed for the journey back at the top again, so the final tidy-up does not undo the organisation that made arrival easier.