By request, I'm bumping this post up over one about Wyoming and the Wyoming Basin, which is likely to be a little long and borderline sappy.
I can speak to a few aspects of hydration systems, and will direct you to other resources for more comprehensive information. I'll break this into two parts, water vessels and water filtering devices. Of course there is some logical overlap, but here it goes...
I'm talking about the things from which you actually drink. In my opinion, you have two options: water bottles and water bladders.
I have only a few good things to say about water bottles. Here they are: water bottles are good for squeezing water out of fast and in a very specific direction. This only seems to be very important when you are trying to clean peanutbutter mud off your chain.
Water bottles are also good for .... Um. Well that about sums it up. I'm not saying it can't be done. It's cheaper to put 4 bottle cages on your bike if you already have the eyelets than to buy a frame bag. So take my advice with a healthy dose of your own perspective.
Water bladders are superior to bottles for two important reasons: carrying capacity and ease of drinking. Most cycling water bottles are 21-26 ounces, or 0.62-0.76 liters. At this rate, you're going to want about 3-4 water bottles to have about 2 Liters of water on you at any time. Volume of water is personal preference. I find that keeping 0.5 - 1.5 liters on me keeps me going between water sources. You might want more. One advantage of water bladders is that they tend to be sized at 1 liter or more. Right away you're getting more water per vessel.
The other advantage is being able to stuff them in a frame bag, backpack, or other hiding spot quite easily. With an appropriate length hose attached, you should be able to drink water at any time with minimal hassle. (Reaching for a water bottle while riding on washboard just isn't comfortable.) Make sure your hose is long enough to run to your mouth without too much craning from your frame bag. Most hoses are designed for backpacks, not frame bags.
The negative to water bladders is that they're less durable. They're more likely to get a small hole or wear easier than a water bottle. Make sure the place where your water sits isn't too crowded with extra junk to prevent rubbing or punctures. Have super glue and fabric tape handy to fix leaks.
Compatibility with your bikepacking system is important. If you're putting water in your frame bag, bladders like Camelbak or Osprey may not work because of the rigid components like the circular "lid" or the stiff "spine" of the Osprey bladders. This is why I found Platypus bladders to work well. The Hoser line of bladders means the bladder is malleable, all around. HOWEVER, this doesn't mean you should be habitually folding your bladders in your bags. I found that repeated folding tended to cause more wear on the bags over time. If you have a small frame bag like me, you're better off buying two, 1 liter bladders and nestling them in side by side instead of buying one, 2 liter bladder stuffed or folded in the bag. I had one bag fail because of folding; Platypus hooked me up at the next town for free.
Lastly, the clear Platypus bags seem to hold up better over time than the colored ones, but I have yet to have a leak in the colored bag. It just looks like it has been through hell and feels more papery than the clear bag (as if a finish had worn off).
Water Filter Systems
I'm using a gravity filtration system. There's a decent comparison page for water filtration systems on Outdoor Gear Lab: http://www.outdoorgearlab.com/Backpacking-Water-Filter-Reviews
I've been really happy with the Platypus GravityWorks system; I've also seen people really pleased with the MSR Sweetwater Microfilter. While I'm traveling in foreign countries, I use the First Need filter as it treats some viruses in addition to bacteria. On the divide, you mostly just need to address bacteria from cattle grazing.
I was a little worried that I wouldn't be able to get enough water in the Platypus Dirty bag along the route (say for example that there's only a puddle of scummy water that you need to drink from). However, I've found that the water sources along the Divide (even in the middle of summer) are volumous enough and frequent enough to always fill the whole 2L bag with no real issues.
It also works quickly. It'll filter 2 liters of water in about 3-5 minutes. And as the name suggests, gravity does most of the work for you. You'll filter water into your clean Platypus bladder, or into your friend's water bottle, or right into your mouth if you feel so inclined.
So do your own research to see what solution works best for you, but I hope this helps answer some not-easily found answers.
Oh, one more thing:
If you were thinking of just wearing a backpack to carry your water, ask yourself if you want to have a sweaty back every day for weeks or months. Then try to find a frame bag or many water bottle cages.
I wear a backpack only when I need to carry more than 2 liters of water at a time (aka Wyoming Basin) . My friend who traveled with a backpack through Wyoming said that if he had to do it over again he would've made the backpack a less essential part of his gear setup. So there you go. Some empirical evidence.