After Oxshott Heath I take a shimmy via little Heath Lane, Water Lane and Fairmile Lane and then down Tilt Rd, taking the bridleway by the cemetary to head toward Bookham Common via Bookham Rd under the M25, through Bookham Common and then through Bookham via Church Lane, Little Bookham Street and Rectory Lane, this brings you out opposite a Chalkpit Lane, which is a BOAT or a RUPP or whatever, that goes straight up onto Ranmore, although its much more pleasant to peel off this half way up and take the bridleway to the left as the BOAT/RUPP is very loose and stoney for the second half.
TBH I reckon after Oxshot Heath you are on the road as much as off it, alhough the roads are pretty much empty.
Hope this helps.