After 2 miles a lot of this leg is off road, so I can only make some suggestions as to where to support your runner, and how best to get to the end of the leg.

From after the start, all traffic should follow the road on the north of the green through Little Kingshill to the A413, then right along the A413 towards Amersham.

To get to the end of the leg from Amersham. Follow A404 to Little Chalfont. Just before entering Little Chalfont. Turn left down Bell Lane. Right at T-junction, at bottom.  First left through Latimer to Flaunden. At crossroads in middle of Flaunden, turn left (Birch Lane).  After 2 miles turn right into Chipperfield Road. The finish is on the right a mile and a half along this road. 

You can pick the runners up at Little Missenden, by turning right of the A413 after a mile.

Or, at the entrance to the Shardeloes estate, by taking the 3rd exit at the roundabout, a mile further along the A413.

The first exit from this roundabout takes you to Old Amersham.  On the right a couple of hundred yards along this road is a lay-by. The runners appear from the right just before this and follow the road to the centre of Old Amersham.

At the centre of Old Amersham the runners go left, (just after Market Hall) through the graveyard and right along the stream. Then sharp and uphill to the Martyr’s Memorial. If you get here early enough, why not run up and see the Memorial and the view.

From Old Amersham, cars should follow A404 (runners join A404 at 7.2 miles into leg but only for a short distance). At 8 miles into leg (see race maps), and just before entering Little Chalfont, take left signed Latimer. At bottom of hill, turn right at T-junction. Then next left through Latimer. After Latimer the roads are narrow and winding, so please drive carefully and give lots of space when passing runners. Also study your maps very well as you cannot always follow route and there are lots of alternatives to get to Chipperfield.