This is my self-styled Redhill to Headley Heath via the A217 and Banstead Heath classic, taking in the best bits of Banstead Heath. OK the bit under the M25 is a bit crap, but you'll not be disappointed by this ride at all.
Most people would look at the OS map and dismiss this ride out of hand. Indeed a bit of local knowledge would say that this would be a poor, rather boring ride. Yet take people on it and comments such as "one of the best rides of the year" or "what a blast" are common. It's a subtle one this.
This particular route is also kind of an introduction to the aea, and could easily be widened to take in a lot more really good riding. Box Hill, Ranmore and Leith Hill are all within a few miles more.
Be warned that the Banstead Heath section will test your muddy riding skills to the limit in the winter. It's a naturally boggy section made worse by leaf mould. I like it, but some moan.