Route from Wembley to Surrey Hills

philw80

I'm heading down to London for a weekend later in the summer for the RL Challenge Cup Final, but taking the bikes as well. Does anyone know of a decent (safe-ish) route from the Wembley area, down to Richmond Park/Hampton Court and out to Box Hill and the surrounding area? I don't know the area well enough to plot a route on Garmin Connect, so was hoping to get a bit of advice on here!