An outside shower helps lessen the amount in the gray tank.
Find high altitude areas during the heat of summer. We are in the Sawtooth Mountains right now where it was 32 degrees this morning and may get up to 70 this afternoon. Up here, you can bathe in the rivers, though I would do it quickly. That water is cold!
We have solar, which is worth its weight in gold. You might invest in a small portable system in place of one of the generators. Generators require one to stay around camp a lot more to charge batteries. During the heat of the day, we tend to be out hiking, exploring, whathaveyou and don't worry about how hot the tt is getting.