The only time I have camped in a campground with power was 3 years ago when I spent a week in Yellowstone.
The trees in the Camp Ground are all at least 80 ft. tall.
It was freezing every night so I used my furnace
I had a flat roof mounted 50 W panel and a group 27 deep cycle battery.
In the sun the battery is usualy at full charge by 10 am. In the trees at Yellowstone
it was at full charge about 1 pm.
My camping is all in Fire safe Areas in National Forests and ocassionally in the Arizona Desert.
I have 12V TV/DVD player which I use almost every night for DVDs.
I have never been short of power.