Places worth stopping / eating include El Pajar (918 693 194), an old yellow barn restaurant set back on the right hand side beside the speed bumps as you enter Lozoya heading east, the cafe on the square in the centre of Rascafria, the chocolate shop on the left as you leave Rascafria, the Sheraton El Paular hotel and restaurant in a beautiful and impressive old monastery some 3 km beyond Racafria, Las Presillas bathing lakes signed on the left just after the hotel, La Isla restaurant hidden at the far end of the second of two parking areas that are clearly signed and are about 200m apart on the left hand side, some 3-5km after the hotel ( La Isla is our favourite simple restaurant in this valley, and after there is a lovely walk to be had along the river, and finally there is some good hill walking and fine views to be had at the summit at Los Cotos, before the road levels out and heads for Navacerrada.
A great road generally but the fun really starts after you leave Rascaria. Great alpine road, well surfaced, with switchbacks, mountain vistas etc. Could be a bit full of hikers and tree huggers in the summer but on a Tues afternoon in October was almost deserted. Rockin' on a Multistrada but would suit any bike.