You should obviously avoid rattlesnakes if at all possible. But if you do get bitten by one, what should you do? What supplies can be brought ahead of time to allow for the best treatment, and what should you do if you have nothing other than standard gear for a day hike? How soon after a bite is medical care needed?
When bitten by a rattlesnake:
As for things to bring to prepare: an ounce of prevention is worth a lot.
Medical care is needed immediately. Get it quickly. The Sawyer Kit is actually reported to reduce the severity of bites, but does not replace the need for care. It may buy you some extra time though.
Running or other activities that drive your heart rate up aren't generally good. It's kind of hard to keep the heart rate down because your first instinct is going to be "panic". If you have more than one person, send the one who did not get bitten for help. There's a bit of judgement needed here. If it's two days to get help, leaving a bitten person alone is not a good option.
Keep the injury low, don't tie a torniquet, don't "cut" the wound to get venom out.
There's really no other good solution.