The challenge comes after two knee operations, with a third planned following an ACL injury sustained while skiing.
Mantle said: “People think I’m pretty crazy, and it’s safe to say they think I’m mad, but my friends and family know what I’m like; I like a challenge.
“I’m looking forward to it. I wanted to see what I’m capable of and if my knees hold up and I’m able to do this, then I’m sure I’m capable of anything.”
Despite the physical demands, Mantle believes his biggest battle will be mental.
“But I’ll be focused on the end goal, why I’m there, and that’s raising funds for a great charity.
“What they go through is a lot worse than what I’ll be going through on the day, and that’s what is driving me.
“My feet hurting for a few days is nothing compared to what some people go through.”
He developed an affinity for KEMP Hospice, based in the Wyre Forest, after visiting the charity as a schoolboy.
Mantle’s original fundraising target was £500, but he has already raised £1,500 and has now increased his goal to £2,000.