Years ago I traveled to Baja Mexico with Greet Tortoise bus. While we stopped at Cataviña to see the cave paintings, I chatted with a lonely bicycle tourist. I remember asking him what was the most difficult part of his trip. He thought for a second, then said - water. In Baja it was difficult to find drinking water.
Now I have been planning a trip through baja of my own. I have read Graham Mackintosh'es first book - Into a Desert Place: A 3000 Mile Walk around the Coast of Baja California. His trip takes him to the extreme - he goes way of the beaten path. Graham distills fresh water from the sea at a times, he is so hard core.
My plan is to stay on the paved road, Highway 1 most of the time. Riding in the morning and resting in the afternoons. My goal is 30-50 miles per day. I will camp. I will carry a emergency dry food rations, and about 6L of water.
Now about the water - instead of giant plastic jug I have been having nightmares about I have invested into two 3L Nalgene CXC bladders, and Terracycle FastBack Double Century hydration pack. According to Bicycle Touring 101 website there are truck stops/shacks every 50KM or so, so there are places to get food and water.