I tried the powder when backpacking like you described when I went on a camping trip last year. The problem is that you need to rinse the Nalgene bottle thoroughly after consuming the Soylent (which means you have to carry excess water, or find a water source relatively quickly). Otherwise it stinks like hell.

I found Soylent 2.0 and Coffiest work a lot better, since their bottles are disposable. Just put it in your trash bag and you're good.