When racing gets under way on Kumara Beach at 7am today, McCaw will join with New Zealand Rugby Players Association head Rob Nicol in the two-person tandem section.
McCaw contested the 33km alpine run section with wife Gemma two years ago, only to fall foul of the terrain and finish at Klondyke Corner with a nasty gash on his leg.
When asked about the alpine section this year, he said his plan was to "not slip over".
But if there is any stage he is worried about in this year's event it is the 65km kayak, saying in jest that he may "just sit in the back and let Rob do all the work".
But on a more serious note, he said that the key was not so much the rapids but to just keep going and keeping the big boat afloat and hoping for a easterly on the 70km bike ride to the finish at New Brighton.
McCaw and Nicol were inspired to contest the Coast to Coast as a team after completing GodZone last year and it was all the messages from Nicol that inspired McCaw to train.
As for nutrition, McCaw thinks he has found the key to success. Baby food.
"It's much easier to digest," he said.
As for stepping up to the big dance [the Longest Day], McCaw said: "You never say never".
Among other ambassadors for this year's race are Commonwealth Games gold medal-winning swimmer Moss Burmester, motivational cancer survivor Jake Bailey, Australian bushfire burn victim Terrea Pitt and world endurance athletes Samantha Gash, Anna McNuff and Holly Woodhouse.