Gather your dogs presecriptions, vet records, shot records and medications. Depending on the length of your trip, you may put a single dose of medications into a zipper bag.
Put a food dish and water dish into a bag. For space saving, try a pop-up travel dish. For added home comfort, bring your dog's every day dishes.
Measure enough food for the length of your trip and pour it into a zipper bag.
Fill a bottle with water to put in the bag. Washed out large Gatorade bottles are perfect.
Pack waste bags for cleaning up after your dog at rest areas.
Put a pet first aid kit in an easily accessible spot in your travel bag.
Pack an extra leash in your travel bag just in case.
Pack a zipper bag of some treats and favorite toy(s).
Put everything in the bag and make sure it's stowed in an easy to reach place in your vehicle.