When I bought the van years ago here in Singgers the first thing I did was throw out the air-con and all those extra batteries, alternators and bullshit belts, pulleys and struts that kept me from getting at my distributor and carb. Got back the head space for the kids bed over the back deck, too, when the condenser units & blowers went.
The van already had sliding windows in the mid-section, so when I threw out the middle seat to put in the table/bed frame, I switched those around back to front so you could reach them and get lots of air when sitting in the rear rear seat. No rain ever comes in, even though the overlap is backwards.
For me & the co-pilot I have a small 12v fan that can swing back & forth in the front to augment the airflow from the no-drafts (which provide a BIG draft???). Having been here so long that I'm used to the weather, I find that's all I really need to cool me down.
We are 90 miles north of the equator.