It does seem apposite, that two of the approaches to the Lombardy Circle of Death, Thornton Road and Mitcham Road, pass entrances to the Cemetery.
Lombardy is probably best avoided, it's the only place that I ever put my Exposure front light onto flashing at night. If I go that direction I tend to try and hit it as fast as possible, and merge into the traffic flow, but it's not a nice junction.
From Saint Georges I'd probably follow the A217 Mitcham Road to Amen Corner, and then cut across the A216 Mitcham Lane, go past Streatham Common Station, and then onto A23 London Road, until the A23 goes off at Thornton Heath Pond, following London Road into Croydon. Then you can either go up Poplar Walk to Wellesley Road, or continue along the pedestrianised part of North End (which I think is legal on a bicycle now, but practicalities will depend on the time of day and amount of pedestrians). After that, the one-ways get in the way, and you'd probably have to go down Katherine Street, north along Park Lane, and cross onto George Street using the pedestrian crossings.