1. Bike: Tires (I replaced before my trip through western colorado because there were relatively no shops on the way), oil change, chain & sprocket (mine had enough miles for the trip, but needed to be changed almost right after I got back), air filter, coolant (replace every 24,000 miles or 24 months - and I mind the months because the coolant breaks down). Maybe pack an extra headlight bulb if you don't have a newer one or one with the super long life. Seat upgrade if you find yours uncomfortable. Luggage if you want it, although I just used a duffle bag, backpack and tank bag just fine.
2. Yourself: Gear modifiable for all conditions rain, cold, wind, heat or any combination of. Jacket with liner and some level of water resistance, gauntlet style glove and maybe a shorty glove, quiet helmet or ear protection, riding pants. Or if you want fancy an aerocrafter suit that can be wore over day clothes. I prefer REI MTS underwear and undershirts because of the moisture wicking abilities and for fighting swamp ass (also in a pinch they are easy to handwash and dry quickly). A plan for how many days before you will do laundry. Comfortable clothes, jeans and sweatshirt (I prefer wool because of it's drying abilities) for when you arrive. If you ride regularly, also maybe want to clean your existing gear you intend to take on the trip. The road trip brings out the smells a lot more after a few days.
3. Consumables: Always keep at least a liter of water and enough calories to survive for a day or 2. I had a camelback bladder and trail mix with me. At minimum your kidneys need 500 mL of water per day and function better up around 1.5 mL. I would also usually start my day with a good breakfast at a diner and with my meal usually get an English muffin as the bread option and ask for peanut butter and jelly to go that I would wrap up and take with me on the bike. This may seem a little extreme but it's just a habit I started when I used to do a lot of backpack trips. I found on the motorcycle it helped because being exposed to the elements I got dehydrated quickly and the extra calories helped make sure I had adequate concentration. Toothbrush, toothpaste, Dr. Bronner soap, hand wipes (see swamp ass comment), meds/supplements. I used Curaphen
http://assets.euromedicausa.com/DBFiles/Greensheet/179.pdf , and Pain X Plus (love the caffeine in there, when I needed a little more than the Curaphen)
BioGenesis :: White Willow :: Item #s 255, 260
And for one final thought, planning bathroom breaks.
[ame=http://www.youtube.com/watch?v=3FOae1V1-Xg]Let's Talk About #2 - YouTube[/ame]
Edit: oh, speaking of youtube, Electronics: I brought my iPhone and chargers, a Mophie battery pack, tablet for reading in the tent at night, GoPro with multiple SD cards, and the Mophie can be used to charge all of that stuff.
