Kate and Will on tour.
Kate agreed with her husband: "It's so hard because there's so much out there".
Before leaving on Friday, the royals will spend the night at the Restormel Manor, a historic house in the medieval town of Lostwithiel.
Although the cathedral was built between 1885 and 1910, the new roof will have a piece of modern history as the couple signed two of the 60,000 slates that will be used.
Jaydon, who has cerebral palsy and uses a wheelchair, had waited for three hours to see William and Kate with his mother Emma Mitchell.
Gladys Perkins, 89, one of dozens of inhabitants from St Martin's island who welcomed the Duke and Duchess to their picturesque home, said: "I said to William, "you haven't been here for a good while" and he said "no".
"I wouldn't say I am a huge fan of hers with posters all on the wall or anything".
On that occasion, Mr. Wayne asked for a picture - and the heir to the throne agreed.
"Oh go on then", he said.
The goal of William and Kate's trip is to meet local organisations, businesses, and charities, as well as visit a number of Duchy of Cornwall projects. However, they did get to visit the most popular tourist attraction of Cornwall because of the weather. The Duke and Duchess sampled a variety of products including the farm's special apple juice.
Things started off pretty slow for the royal couple, with Kate pouring a pint of the bar's famous alcoholic Rattler cider. Support groups are also on offer to help children and teenagers. The program's goal is to reduce anxiety in children and improve their mental well-being.
We can't imagine having a drum kid around two young children would be a great idea, so we totally understand where William is coming from with that one.
Sam, who also has one daughter Ellie, 13, said his initial intention was just to follow on from his earlier selfie with Prince Charles and he has been staggered by all the attention his actions have caused. William admitted it took "an awfully long time" to know what he wanted to do.
They visited a flower farm and a community hall on St Martin's but were not able to make it to St Mary's.