Sleep on your boat
Virtually every river rat I boat with sleeps on their boat. That's worth 10-15 degrees right there. I sleep on a mesh roll-a cot on the boat, so that doubles the evaporation off you. You also don't have to find a spot or set up and take down the tent, or move your stuff off your boat. That's 30 minutes in the morning and 30 minutes in the evening I don't spend packing. Buy a used bimini from a powerboat, and you have rain protection at night and shade all day. Less sunblock application. My brother works with seniors in Phoenix, and he asked them how they got along without air conditioning pre-1950's. They slept out on the porch in a damp sheet. Humans are adaptable. We evolved in equatorial Africa for christs sake. Here in Utah I frequently ride my bike around in mid-day heat. You find a sprinkler to ride through every 20 minutes. I floated Grand in July, it was 114 at Phantom. So what? A couple people got panikey hot. I was drinking beer all day. We float Cataract mid-summer every year too. I don't go boating to haul a bunch of engineering projects along. Change thyself first.