Length: 13.75km (8.5 miles). Toughness 6/10).
09:42 Horsham train from London Bridge (Sutton 10:22, Epsom 10.33 etc), arriving Box Hill and Westhumble at 10:46 (or 9.54 Guildford train from London Waterloo and change at Epsom to connect with the 10.33 Horsham service)
Return trains from Box Hill at xx:33 to Waterloo, xx:56 to London Bridge (not Victoria)
This short, strenuous walk will give you a bit of workout. It takes in in a succession of hills: Norbury Park, Mickleham Downs and finally Box Hill itself. There should still be some good autumn colour in the woods. I'm proposing Short Walk 1 via Juniper Top, but you could choose to do Short Walk 2 or, if you want a tougher walk, the full Main Walk.
There are two pubs to choose from in Mickleham. The Running Horses (RH5 6DU 01372 388422) and the King William IV (RH5 6EL 01372 372590). I'd suggest booking a table if you want to eat at either. A nice picnic spot is the churchyard of St. Michael and All Angels, Mickleham where there are plenty of benches
Later refreshment options are the indoor café at the National Trust Visitor Centre at the top of Box Hill, or the spacious but cosy Stepping Stones pub at the end of the walk, five minutes before Box Hill and Westhumble station.
You'll need to bring the directions from the L=swc.64.a page. Click on "Short Walk 1, via Juniper Top", on this walk's web page to just see that route.