I'd say starting with short tours is recommended - mostly to sort out issues of what to bring. For years all of my tours were close to home - the longest only involving three successive days of riding. Usually I'd ride for a day or two, camp for a few days, then ride back home.

I live about 3 miles from a nice state park with a beautiful hiker/biker spot. Some kids I teach (6th grade) wanted to try bike camping. We rode the 3 miles, camped overnight, and rode home. A couple of parents drove over and had dinner with us. It wasn't a hard-core tour, but those kids had a great time! That's the whole point, right?