My wife's health demands she have access to dryer air than we often have in this area. Before we got our camper, I would set a window unit on a milk crate so it could blow thru a window screen. I used a tarp as a boot to keep most of the air from escaping. Quilt between tent and rain fly helps in heat or cold.
Last time I pulled into a state park for overnight in the tent I started to unload gear on a electric site, then thought "What am I going to plug in?" Moved to another site, used my inverter and starting battery to grind the coffee.