Mooh, at the two festivals I mentioned I haven't seen changing stations in the men's rooms, I suspect they don't have them in the ladies' rooms, but I never asked.I've never seen a guide dog there, so I assume it's bring your own supplies and dispose of waste in a toilet or port-a-pot (unless a closed plastic bag makes it OK to put it in a trash can).
Day parkers park on the grounds, Winfield has a shuttle wagon to cut down on the walk to the music area. Camping is on the grounds, and part of the campground is adjacent to the music area. Some folks choose this part of the campground for the geographical convenience, others choose a farther-out spot for the relative isolation, latecomers take what they can get.
All stages have open seating, which means first come first served and move into a better spot if it opens up. Some stages have installed seats, some are bring your own chair. Some people leave their empty chairs for a while, and usually folks respect that space, but there's no rule about it. Most people do a fair amount of stage-hopping, going to different stages at different times to catch the particular acts they want to see.
Tickets are for a 24-hour day, midnight to midnight. A multi-day ticket is necessary to drive into the campground (weekend ticket only to get into Winfield before the festival proper starts). If you have a Fri-Sat ticket and arrive Thu evening, you wait by the entry station until midnight, officially Fri. If you want to get in Fri, you buy a Fri ticket, whether it's 9:00 AM or 11:30 PM (this makes it somewhat unattractive as say, a one-evening venture).