I bought a small washer that weighs like 14 or 15 lbs and it washes and also spins. It's very lightweight and takes as much space as a 5 gallon bucket. I've used the bucket method before and this I like better. My wrists get pained from all the wringing. It was on sale at Camping World and I said, oh what the heck, I'll give it a try. LOVE IT. Brand name is BASE CAMP. But there is a Base Camp one without spin. The spin was essential and that's the one I got.
Speaking of soft water, I have a small barrel that's food grade that I put where the water falls off my awning. I made my own cistern for outdoor washing. It holds many gallons, and I can pack towels and linen and blankets in it during travel, so it's not like it's a lot of trouble to carry it with me. That water makes the best soft water for washing clothes. I cover it when it's not filling because I don't want mosquitoes to get in it, but it can sit there ready to go, filled with soft water. It rains almost every day in Florida! No shortage of water here!
The washer does have an AC plug, so I have to use the inverter when boondocking, but it's designed to use very little power. I use the eco friendly soap and where I camp it's okay to let eco gray water out on the ground, so I set it up away from foot traffic and let it do the hard work. The clothes come out soft and the soap spins out well so that they aren't on the line very long.