I think 10k will seem a lot to a non cyclist!
Not all children are the same, mine cycle regularly with me but the 8 miles (4 out and 4 back) of cycle path is plenty enough for them. The youngest won't even tackle a hill, she gets off and pushes.
If you can plan a picnic rest after about 5miles with the "official" target being a further 5 miles, the fitter riders could then do that extra ten and be back before the less able riders have finished their sandwiches.
Not all children are the same, mine cycle regularly with me but the 8 miles (4 out and 4 back) of cycle path is plenty enough for them. The youngest won't even tackle a hill, she gets off and pushes.
If you can plan a picnic rest after about 5miles with the "official" target being a further 5 miles, the fitter riders could then do that extra ten and be back before the less able riders have finished their sandwiches.