Camelbacks are good for lots of water and carrying things. They have more pockets for carrying, and more water for water if you buy one large enough. I also use a small seat bag for tire levers, co2 cartridges, and a multitool.

this plus three nice sized pockets in my jersey do it for me. That is one of my pet peeves of course with women's jerseys. Sometimes they don't have enough pockets or enough room in the pockets. Of course, I don't carry more sunscreen usually and a small one would work for me. I carry, extra jacket, (rain or warm), sometimes tights, since I live in the mountains and weather can change in a second, my tire changing stuff, with a tube in my back pocket or my camelback since tubes often get a hole in them in a small underseat bag from the zipper, extra food - a bar or two, and gels, a banana if I want, or pbj sammy, chapstick.

That's about it as I recall