We normally set off from the m53 at 6ish. You don't need to set off at 3am, you're missing a night's sleep that way.
I think 2010 there was really bad traffic driving in on the Wednesday so we changed our route.
We come off at m5 junction 22 and go through Mark, Wedmore and through to Wells. There's never any traffic on them roads. Head to North Wooton and get on the Higher Westholme Rd. This will bring you out right into Pilton by the Crown pub. From there you can pick which car park you want.
It takes 4 hours hours ish with one stop. We stop at asda cribbs causeway in Bristol. It's a good place to stop for any bits you may have forgotten.
We've been using this route for years and have never been stuck in traffic