Congrats on the century. The first is always special.

As far as displaying/using maps/cue sheets, you don't need a handlebar bag (though they are quite useful). I've rigged up a map mount on my aerobars, seen others do the same thing with a heavy-duty Ziplock bag and a couple of cable ties on their handlebars (both straight and drop), and seen at least one guy who has his cue sheet on a necklace he can pull out of or tuck back into his shirt while riding. Do a quick internet search and I'm sure you'll see what is available out there.

FWIW, I tried carrying 2 or 3 - 650ml-1L water bottles and/or a 3L camelbak before finally settling on 2-1.5L water bottles. I always sweat a buttload and ride in the "humid South of the USA" so this is a near-necessity for me. I can also carry a 650ml Gatorade in the back shirt pocket or in my rack bag if needed. I tend to err on the side of caution hydration-wise.

Keep riding.