They describe the trip as "a holiday and a pilgrimage" and, though they have already funded the trip for themselves, they thought they'd use the opportunity to raise money for two charities while they were at it. The two charities are Mary's Meals and the Cardinal Winning Pro-Life Initiative.
Mary’s Meals provides a staple, daily meal in schools for children in some of the poorest countries in the world, thus fighting poverty through tackling malnutrition and encouraging education. The Cardinal Winning Pro-Life Initiative provides non-judgemental practical, spiritual and emotional support for mothers in the UK, struggling with crisis pregnancy and the prospect of bringing up a child alone.
They promise to keep any sponsors in their prayers en route.