My first van was an E150, low top passenger van. I took out all the rear seats and built out my simple camper. Used a battery operated camping lantern that ran off either regular C batteries or had a small solar panel built on that recharged the other batteries. Also used a candle lantern. Recharged phone and tablet from starter battery, never a problem. Propane stove and heater (little green bottles). X-treme ice chest. I did carry an extension cord and small electric heater. If it was going to be a really cold night (like below 25 degrees), I would check into a park with electric hookup, run the extension cord out a small vent window for the heater, more for my little dogs than for me. An O2 Cool battery fan for really warm nights. Jugs for water. Coffee can and small bucket lined with plastic bags for toilet. Collapsible basin for washing and bathing. Texas to Maine, then to Alaska, California, Colorado, and everything in between.
Then, I graduated to a Pleasure Way Class B. Very nice. Very big PITA, all those systems to maintain. One trip to CO and sold it. Am now setting up my mini van similar to the first E150. So easy to use, so simple. For those who like all the bells and whistles, go for it. Me, KISS.