right, that's where the judgement comes in. we didn't ride roads when they were starting out. don't remember the age we first did some roads. we also use bike flags so everyone knows the 4 of us are together, if anyone yields for us they know to yield for all of us. lots included in "judgement" such as road type. one place we bike on the road is Commercial Street Provincetown, MA which is mostly full of people anyway. Other roads are Ocean View Drive Wellfleet, MA which has great visibility. Cape Cod can have some dangerous roads and intersections but if you use good judgement some roads can be navigated. We do switch off now that my kids are teenagers.
I lead usually because I have the most experience and will make the decisions of where to ride and they can follow my line and speed. I can't shout ahead and say any directions and expect them to hear me.
here is one of our rides from the campground to a beach
http://goo.gl/maps/XLVPP
http://goo.gl/maps/HHQIB
this is another ride we do but it is mostly rail trail
http://goo.gl/maps/nXpZY
and then of course all the roads around here are pretty awesome