I'd say we tend toward the minimalistic side.
We camped in the 70s and 80s in bare station wagons and vans and a sailboat using cheap foam mattresses, coolers and backpacking gear. We did eventually get a VW camper van and an older Chevy class B but they didn't have a house battery, water system, or heater.
After a couple of Aerostar window vans in the 90s we had an Econoline with a fiberglass top. We put 250K travel miles on that one. I did build a bed platform but we just used a cooler, water jugs, butane stove, battery-powered lamps, Buddy heater and porta-potty. We somehow managed to keep our laptops, cameras, cell phones, Inreach, and Fantastic Fan powered just using the van's starter battery.
When I bought my Hawk shell in 2015 it came with owner-added fresh and grey water tanks but I've never used them. That Hawk does have a house battery for the furnace and lights and does have a stove. I keep the battery charged with a DC-to-DC charger. That charger has a solar input so it would be easy to add solar but I've not needed it.
In our latest van we continue to just use a butane stove, ice cooler, water jugs, Buddy heater, etc but I did add a house battery-- just a battery in a box like you do for a trolling motor. We use the house battery for a vent fan, LED strip lights and (in coldest weather) a portable diesel heater. I keep that battery charged with an automotive-style charger plugged into a small inverter. We continue to charge all small batteries via the van's 12-volt outlet (i.e., while driving).