Maybe stating some obvious things or things you've already got in mind/have checked, but:
- check spare, jack, tools in tool kit
- check the spare
- give your drain holes a check in case you get caught in some random poor weather
- spare headlight & taillight bulbs
- check the spare
- take a look at all that plastic panelling under the front of the car, make sure nothing's loose/missing
- hats?
- polarized sunglasses?
- air filter recent/new?
- sweet picture-taking skillz?