In reply to Climbyclaudie:
If the weather is good and a stable forecast it's safe, depends how strong the kids are.
We did Snowdon as a family via Rhyd Ddu and the Ranger when we were 4,7 and 10.
The Mindfordd is more picturesque, the Pony simpler, but up the more boring side of the mountain, you don't get to really see its architecture from that side.
The minfordd is steeper and whilst not craggy is a rougher pass and traverses above cliffs, but not dangerously so.
Both around 10k up and down, 2500ft of ascent, Pony slightly less. 4-6 hours at a guess... depends how quick they walk and how many photo's/stops.
I'd go Minfordd personally.
Post edited at 11:12