Loader, it's fun to have someone here with lots of basic questions! Your questions are pretty easy for us to answer.
more gallon to take with me, too heavy.
Really? With all the stuff you're carrying, a few gallons of water is practically nothing.
How safe is a bicyclist on the road?
Safer than most people think, and probably safer than you are at home. Getting hit by a car is your biggest risk. Getting attacked by a psycho killer or a grizzly bear are your smallest risks. Having your stuff stolen is a medium risk, but you can control that risk by being careful.
I’ve never been in a place on all my tours where water wasn’t available at some point in the day.
Rare, but such places certainly exist in the U.S. I've carried as much as three gallons for crossing the Mojave desert.
Do you need to filter water or boil enough?
You can carry a filter if you want. However I've found that, except for wilderness touring on a mountain bike, places that lack available potable drinking water also lack available surface water to purify (at least in first-world countries).
What kind of diet do you prefer on the road?
What kind of diet do you prefer at home? It varies by person and by how much you enjoy cooking, and if you have dietary restrictions. I can get by just fine with cold food, so I don't feel the need to cook (although I do anyway sometimes, just for fun). I take non-perishable food (energy bars, jerky, peanut butter, candy bars, pop tarts, etc.) for emergencies and the rare places where there is no food available for purchase, and consume perishable foods within a few hours of purchase. I sometimes carry a small alcohol stove for making dried foods such as oatmeal or rice.
