Traffic in South Wales; do I have to leave at 5am?

[Epictantrum]

Hi, I'm travelling the (hopefully) 5 hour journey from the midlands down to St. Davids next Saturday....eeeek!
Does anyone have much experience of this route (m5, m4, a40 pretty much all the way I think). Will it be as bad as the Devon/Cornwall routes? Should we leave at the crack of dawn? Any tips for where to stop with a dog and 2 kids?
Thanks

We regularly do S Devon A38, M5, M4, A40 to Pembs. The M4 in S Wales is grim. Once past Swansea it eases. St Davids and surrounding area is lovely and peaceful. Much quieter than Devon and Cornwall.

Not sure about stopping with dogs. We have broken the journey at Castle Coch just off the M4 near Newport. St Fagans outdoor museum near Cardiff, Ikea (we don’t have one near us) and Caerleon for the Roman remains.

It's nowhere near as bad as the Cornwall routes and much quieter when you get there too - no massive queues to get to beaches.

We stopped at Caldicot Castle on the way (recommended by a helpful mumsnetter!) and it was lovely.

You can avoid some of the worst traffic by taking the M50 rather than staying on the M5. Another good stopover might be Tredegar House, which is just off the M4 at J 28 at Newport.