I hope I hit all your questions, if not let me know. For the extra day we walked to Snow King resort and did the alpine slide, putt putt golf, and scenic chair ride. Most people took their kids on the alpine slide for the free morning, but this was all they had time for. If you only had time for one, I would do the slide.
Every night goes down to the upper thirties, lower forties. We never had anything more than a pair of jeans and a sweatshirt. the daytime was in the seventies. Do not pack any dressy clothes, i can not think of one place you would wear them.
Everything in Jackson Hole is within walking distance of the hotel. All the restaurants are very casual. For breakfast our extra morning we went to the Bunnery. There was something for all tastes there.
As far as motion sickness, I had no problems, and trust me i am the worst. There is very little bus time. The long trek is to Yellowstone, and back. Each way maybe 1.5-2 hours. There is a half an hour ride each way for the white water rafting on the rafting company bus. The ride on Jenny Lake is basically to get to the trails, 5 minutes max.
As far as bottled water, it was readily available. the guides really pushed water on everyone to prevent altitude sickness. You will not need your own water bottles.
The two things I wished I would've packed was binoculars and one of those lanyard things that hooks on the neck of a water bottle. Disney called every family in our tour and warned us that it was currently snowing in Wyoming prior to our departure. So everyone packed less summer clothes and went heavy on the warmer. After 4 days most of the group was running out of shorts/tshirts, and between the 4 of us we probably had one whole suitcase full of clean jeans and sweatshirts. The snow was just starting to melt at Brooks Lake, so anything off the beaten path is MUD. If you do not have hiking shoes, than bring that pair of shoes you really don't want anymore.
Enjoy your trip. I am so jealous.
