Great stuff! We'll be following you to see how you're getting on!
It will be a challenge, and you really need to get some miles in before you attempt it, I mean, LOADS, unless you plan to take a loooong time, of course!
I've done a couple of 100 mile rides (ca. 6 hours each) and road about 40km every other day to get fit; get a comfy saddle! 😄
Ray has been a keen cyclist all his life, good person to ask for advice.. :)

Good luck, Lewis! You can do it!