After much trial and error when I first started using an air pad, I now pump it up pretty full, then lie full length on it, letting out the air a little at a time until the mattress is squishy enough to be comfortable but keeps my hip off the ground when I lie on my side. Also, testing new gear at home is usually a good idea.

I don't particularly like the idea of showering or skinny dipping outside with the mosquitoes or in view of any passing public. Instead, I sponge off critical areas in my tent at bedtime. That seems to work well enough. I usually have a little lukewarm water left in my cooking pot so I don't have to freeze.
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May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey