But there was some ''conspiracy'' going on that Williams did not know about - until son Pete walked into her kitchen last Wednesday from Western Australia, where he works as a contract fencer and musterer, and announced he was also taking part.
She was ''shocked, amazed but very, very happy'', she said yesterday, during a brief stop beside the Clutha River at Clyde.
Topping it off, Tairua's daughter-in-law Danika was also on the trail so it was a real family event.
Williams' late husband Maurice was a cavalcade trail boss - and a real identity - and the cavalcade had been a major feature in their lives.
Making no concession to age, Williams chose one of the tougher riding trails to take part in, riding borrowed steed Dakota.
''It's a challenge; you've got to have a challenge,'' she said.
Asked what she loved about the cavalcade, she said it was ''just like a big family'' and she enjoyed meeting the people taking part and the friendships forged.
Butler said Williams was a very special character, '' a bit of a legend, really.''