The record-breaking batsman, who has not played a one-day international since September because of a mystery illness, batted fluently to help his side pile up 267 for eight from their 50 overs.
Gritty left-hander Shivnarine Chanderpaul top-scored with an unbeaten 97, and opener Chris Gayle continued his good form with 44.
Free State made a bright start to their reply, with Jonathan Beukes smashing a quickfire 96, before losing their momentum to finish on 226 for eight.
Seamer Corey Collymore was the most successful bowler for Carl Hooper's side with figures of three for 20, trapping each of his victims lbw.
West Indies, World Cup winners in 1975 and 1979, begin their campaign against hosts South Africa on Sunday in the opening match of the tournament.
