In reply to CLYoung:
I'd say don't worry too much about the logistics, provided you pick a good weather day the worst that is likely to go wrong with logistics is having to walk a bit down the road until you find someone at home so you can re-book the taxi (might cost a bit but as a family you are just as likely to get offered tea and cakes and a free ride back to your accommodation).
As long as the boys are capable of walking the distance then they will have an adventure on one of the best non-scrambling ridges in Snowdonia.
I'd always go for an E to W traverse, especially with people who need 'confidence building', I have taken friends this way on numerous occasions to help them become more used to steep ground. The initial ascent can look quite intimidating to those who are not used to scrambling (once up close it is easy). I'd be tempted to take the boys up that way and try to relate the experience to something that matters to them, this could be a subject that they struggle with at school or just how to ask the cute girl for a date - just make sure they still have an enjoyable adventure if you choose to use the day to 'educate' them.