South Downs - Any road recommendations?

[C70R]

A group of us are planning an early morning weekend run from London down to and around the South Downs, before the weather completely ruins our fun. While I know the area is riddled with 'decent' roads, does anyone have any suggestions for the brilliant routes/roads?

[C70R]

Thanks both.
We'll be heading out from Central London, so that would be our 'entry point'. However, once we're there we would be more than happy to do a bit of exploring.
We would be leaving early AM on a weekend from London, if that helps.

[C70R]

Thanks both. Massively appreciate you taking the time out to share those routes. I've plugged them into to Google, and we'll make a call on which route on Saturday evening based on how bad the post-rugby hangover is likely to be.

[C70R]

All duly noted, with thanks.

[C70R]

Just to say a quick word of thanks for the recommendations. Ended up starting a little later than desired thanks to a hangover, and (barring a road closure that caused a few mins of chaos) enjoyed a great little blast.

We made it as far as The Cricketers in Petworth, and enjoyed a great chat over coffee with a chap in a lovely new Morgan V8, before heading for home.