This is the help 'Pink Panther' has offered on the Urban forum:
"At last an afternoon game at our temporary home without being inconvenienced by rail engineering works. If you haven't managed to do any of the evening games, or the Worthing and abandoned Dorking games, this one should be easier.
Trains from Peckham Rye, East/North Dulwich; change at Tulse Hill for Mitcham Junction, then one stop on the tram to Mitcham, 5 minute walk to the ground. (Or if the Wimbledon train arrives first at Tulse Hill take that, then tram from Wimbledon to Mitcham.)
Direct Half hourly service from Elephant & Castle, Loughborough Junction, Herne Hill, Tulse Hill to Mitcham Junction, then one stop on the tram to Mitcham, 5 minute walk to the ground.
Northern Line from Kennington, Oval Stockwell to Morden, then 118 bus from outside Morden Underground station to the ground. Buses every 11-14 mins, 6 mins journey time.
Buses 118 from Brixton via Streatham to the ground and 201 from Herne Hill via Croxted Road and Thurlow Park Road to Mitcham tramstop are other cheaper options. "