I hiked the AT south starting in Harpers Ferry. I planned to go 100 miles to Big Meadow over 10 days, so the only feasible resupply points were on day 2 and day 10. (There was another one in the middle, but it was a 4 miles to town, and I didn't really want to spend half a day making a supply run, so I didn't consider it feasible.) To save hiking into town, I just carried enough for 9 days at the start, because I planned to stop at a hostel en route.
There wasn't any water source during the first 10 miles and it was 83 degrees when I set out, so I carried more water than normal -- I have a 100 oz Camel Back in my pack, and I had it full. I thought about dumping some of it to reduce the weight, but as it turned out I ran out of water just as I reached the first water point. After the first day I kept my water level about 1-1.5 qts on hand, depending on how far it was to the next water point. Most often the water points were about /4-1/2 mile off the trail, usually downhill, so it was easier to just hump some extra water than make the lengthy round-trip to resupply.
There wasn't anywhere to swim for laundry, but the weather turned to cold rain beginning on the second day and I ended up wearing almost all of my clothes all at once, except for spare socks and undies. Even so, they were only 7.5 oz. (I weighed EVERYTHING that went in the pack.) By the time I hit 50 miles my boots were soaked, so I was glad to have dry socks to rotate.
