Hydration pack such as Camelback or Platypus or
equivelent. I recommend one with the large 100 oz. (3 liter) size bladder,
as there can be long stretches between places to refill, and staying hydrated is
important. The pack gives you a place to carry other items as well.
Helmet. Street, dirt, or hybrid... it's your choice here. Depending on the type of helmet, don't forget goggles as well.
Sturdy riding gear. Boots/pants/gloves/jacket, plus any other protective gear you wear.
Earplugs. For the wind, motor, or the guy snoring next to you, you should bring a pair or two. Don't say I didn't warn you.
Comfortable street clothes. Also, because the support truck may arrive to our destination after we do, you may wish to carry with you on your bike or person a comfortable pair of shoes or sandals and a pair of shorts or lightweight pants to relax comfortably in until it arrives with our gear.
Map of Baja, Mexico. You don't need it, but if you're like most people, you'll like to follow along on the map where we're going and where we've been. A good general purpose map is the Baja North Adventure Map by National Geographic. Amazon sells them for about 11 bucks.
Camera/Phone. Don't forget the charger.
Lip balm. Forget it and you'll regret it!
If your riding gear has few pockets, a fanny pack can be a useful and easy to reach spot perfect for your camera, lip balm, wallet, etc..
Swimsuit. The Sea of Cortez is pretty fricking tempting at Gonzaga Bay.
Flashlight. Or preferrably, a headlamp. Don't forget this one. When the power gets shut off at Mike's... you can't see a damn thing.
Driver's license. Preferrably an Enhanced Driver's License. Kill two birds with one stone.
Passport (or an Enhanced Driver's License). Forget it and you may get the glove entering back into the US!
Mexican motorcycle insurance paperwork. See the section on Insurance.
Medical/Evac insurance paperwork. See the section on Insurance.
Cash. For food, drinks, souvenirs, bribing the police, etc... Just kidding about the police! Credit cards are accepted almost nowhere in Baja, and cash machines are virtually non-existant where we'll be travelling. See the FAQ section for more info.