Buy day return to Victoria and a single ticket from Clapham Junction to Putney. Catch 9.21 from Hove change at Clapham Junction for train to Putney (5 min journey). From Brighton catch the 9.14 and change at Burgess Hill to pick up the Hove train.
Walk the Thames Path south with early coffee stop, view 2 churches, 2 parks, choice of restaurants or cafe for lunch, Battersea Power Station, optional tea stop, modern architecture by famous architects. Return from Vauxhall Bridge by bus to Victoria Station for return train.