If water is an issue, it's hard to beat a camelback. Camelbacks have 2 huge advantages. The first is obviously capacity. The 2d is that you can fill that sucker full of ice. It is a near religious experience to be drinking cold water 4 hours into a ride. It will do wonders for lowering your core body temps. Plus you can then fill the bottles on your bike with 1/2 gatorade and water.

For a 3-4 day trip, you have a choice to make between full panniers, tent, cooking gear, etc. or latch onto the lightweight camping philosophy. Both are perfectly good ways to go camping touring but you'll want to decide which one is the right one for you before you buy your bags obviously.