Yellowstone National Park questions

I have reserved sites at Madison CG several times. I just tell the clerk when I want to arrive and how long I am. Never had a problem. I general stay a week, but last time I made reservations I got a call back about a month later and was asked if I would like a few more days. Seem like they got a cancellation and wanted to keep the site occupied. Of course I took them.

I run my generator during the allotted times if I am present.