Wifey says I travel with nothing but a toothbrush and a credit card, but in my defense I add:
1. Electrical or duct tape
2. Plyers
3. Two screwdrivers
4. Shop rag, all in a sealable baggy in the bottom of the low side saddlebag
5. Fuses in the fuse compartment
6. Original gas cap in case the chrome one wanders off
7. Sunscreen and lip balm
8. Aspirin and allergy pills
9. Accurate tire pressure gauge
10. Most important, water and lots of it. You'll drink over a gallon a day.
Some of these live in the saddlebag, somelike the HD map get added when I travel outside my usual areas. Also carry extra batteries/charger for the phone and camera, a notebook for recording expenses and ride observations, an envelope to keep receipts, backup glasses. Don't worry much about rain as I see so little of it here in the desert. Do carry the textile jacket liner, electric vest, extra gloves, and/or the evaporation vest depending on the season/weather. For short jaunts carry a really ratty street-find hoodie.
I stay away from sugar, alcohol, and caffeine during the ride due to the quick boost then letdown. They taste that much better at the end of the day.
Enjoy.