Do all groundhogs live in tree stumps?

Photo from wikimedia.com.

No, most groundhogs live underground in tunnels they dig themselves.  The main entrance to the tunnel is usually a pile of dirt.  The tunnel often goes straight down for about two feet, and then turns into rooms for eating or sleeping.  The groundhog often digs more than one tunnel with more than one "door."  Groundhogs usually live where forests meet fields or yards.

If you dug a home underground, what rooms would you put in it?  How many doors would you dig?