My two cents:
For short trips, the clothes go into a set of mesh laundry bags. One bag for undies and towels, one bag for light clothes, one for medium, one for darks. They come home, and get washed.
For medium trips, same as above, and I hit a laundromat. I first wash stuff I don't care about, then the undies and towels (twice with bleach), which cleans out the washer. Then, follow up with the medium and then the dark clothes. This helps mitigate things in case the previous user of the washer used it for their pets.
For boondocking trips, out comes the five gallon bucket, the Bronner's soap, and the plunger. The advantage of this method is that I can wash the clothes, and then toss the water from the bucket outside, as opposed to having it occupy space in the gray water tank. To dry the clothes, in colder weather, I put them over a floor vent and aim a Vornado fan on them. In warmer weather, I hang them in my truck, crack the windows and let the greenhouse effect dry them.
Of course, one technique I've seen used, is in scenarios where one doesn't have enough water or whatnot for doing laundry. Stick the clothes to be worn again in the freezer overnight. When I was in college, I had a foreign exchange student who was proud of the fact that he never washed his jeans throughout the entire college term, and when they started to smell, he would just stick them in the freezer.
