Drawing from experience with Mount Rainier, I did not want to carry again all that camping gear up the mountain. So I decided to go there the evening before, sleep in the car, get up early, and do the whole thing as a single-day tour. This has the additional advantage that it is not necessary to try and hunt for a camping permit, and on the other hand to be still early enough at enjoy sunrise at an upper elevation. So I took off at 3:15 AM from the parking lot, passed the campsite at 6:45 and reached the summit at 8:15. I enjoyed the marvelous views from the summit for two hours, left from there at 10:15, and reached the car at 3 PM. You can deduct about one hour on the way up and more than 1.5 hours on the way down for taking photos and chatting with people, so I spent a total of about 5 hours going up and 4 hours going down. I had taken plenty of water with me, but needed only 2 liters because it was rather chilly in the morning and moreover I try to avoid sweating by getting rid of superfluous clothing as early as possible. I should have brought my crampons, though, since the snow on the very small glacier was very hard and slippery in the early morning, but on the way down it was perfect. The scrambling near to the summit has difficulty level I-II on the UIAA scale, so moderately easy, but slightly exposed.
So, my advice: go early, go light, and don't toss wildflowers at marmots ;-)
And: glory to God, the origin of all that admirable and enjoyable creation.