The story begins with a werewolf attacking a couple I think in car. In one particular scene the werewolf is attacking a family in their RV and eats the child.
This is a long shot but could it be Clive Barker's Rawhead Rex (1976)? Not a werewolf but a bestial god/monster.
Rawhead it was called because its head was huge and raw like meat. It was the last of a line of kings dating from before civilization, before Christ, when England was forest all over... and the home of unspeakable horror. The most famous and powerful story came from Clive Barker's Books of Blood is here unforgettably illustrated. The incomparable talent of Les Edwards brings ancient evil to life.