From my self contained cycling / back packing list.
We carry one 2 1/2 gallon zip lock bag with a very very small bottle (one of those 2" long squeeze type bottles) with woolite in it. That is your washing machine for your clothes and your shower bag for personal clean up. When hiking we carried things is 3's. Wore a pair socks, drying socks and had a dried pair. The same with t's and skivvies. You use the zip lock, very small amount of woolite and water ad just soak your socks and underware in camp. rinse in the stream and hang to dry. You will have clean under clothes for everyday and that is most important.
I never go on a trip with out a travel size container of Gold Bond powder. Good for your feet and even better for chaffing in other areas. Hiking with chaffing in private areas can be a little tough.
We also used a lot of the dry Lipton soups and meals that come in small bags. The just add water type. They are very light. You can get tuna in a pouch now also which is a great snack. If you need bread, we carried pita bread which is flat and has a pouch you can fill with tuna, peanut butter/jelly etc. The next time you are at a restaurant grab some of those individual containers of jelly and peanut butter. They are small, light and real good when you are hungry for a snack. Carry these in a small zip lock just in case the come open. Keeps from getting everything else all sticky.
Almost every large grocery store, Walmart etc has free condiments in the in the deli aisle. grab a handful of mustard and mayonnaise packets. No need to refrigerate, they are small light and taste real good with your tuna when you are hungry.
Every food item I mention comes in foil or plastic (no cans = no weight).
Dump the spotting scope and use good binoculars.
Have fun.