My wife and I,along with our 2 boys and my 2 nieces camped first in a pop up and later in a travel trailer,most times without electric. We were in Yellowstone in May. We stayed in Madison Campground and they allow generator use from 8am to 8pm. So if the girls need to use a blow dryer or charge their phones they can do it when you run the genny. Have them use the campground bathrooms during the day so you don;t have to dump tanks and refill water. There are no showers in Madison but there are pay showers at some of the other facilities.During the day you will be driving all over the park so phones can be charged in the car/truck. Be aware most places in the park don't have cell service.My wife has Verizon and I have Sprint.It seems that Verizon had more coverage.If you want all the amenities you could stay in West Yellowstone. But it's an 18 mile drive to get to Madison and another 16 miles to old Faithful which is why you should stay in the park. As to why the NPS doesn't expand their campgrounds or add hookups is probably because of the environmental lobby. Anytime the NPS or Forest Service want to modernize or expand, the environmental lobby opposes it and sometimes ties it up in court.To me, I am fine with the way they are. Many Forest Service and COE Campgrounds have electric, at least here in the east and south.
