The cycling duo have already broken the Guinness World Record for the largest GPS drawing by bicycle (team), which was 761km and are set to “smash it” further, according to Mr Charles, who is from Bournemouth.
He told PA: “We have already cycled 1,100km and will be riding another 1,200km.”
He added: “The situation in Afghanistan was hitting the news just as we left.
“It’s certainly been uppermost in everyone’s minds while we’ve been riding.
“Everyone we meet seems to be aware of the horror of what’s happening and it’s been heartening to find that most people we’ve met show great compassion towards those forced to flee their homes.”
The pair described the hospitality of strangers as a “fantastic highlight”.
He said: “Wiltshire has been the most generous county so far in terms of donations.
“It’d be unfair to pick out anyone in particular, but Laura and Jon at Bulstone Springs gave us full use of their glamping facilities, and also made us a homemade tiramisu.”
Both spoke about their joy meeting Jon Cousins, the mayor of Glastonbury, after they beat the previous world record distance on the Somerset Levels.
Mr Charles said: “The mayor bought me a cup of tea and Georgie a Guinness and regaled us with the wonderful legends of Glastonbury.”
One of the team’s cycling crew spotted Gordon Ramsay on the first day of the cycle, who was having a coffee at a trail-side cafe.
Mr Charles said: “She slammed on the brakes so hard that she fell off.
“Gordon Ramsay was out for a bike ride himself and happily signed our Guinness World Record logbook.”
Mr Charles had fond memories of playing his bugle after reaching the top of Dartmoor and Exmoor, which left the ponies there “surprised”.
In terms of planning the route, Thighs Of Steel founders Harri Symes and Oli Kasteel-Hare came up with the idea to do a GPS drawing of Refugees Welcome.
Mr Charles said: “Georgie did most of the planning and we use Komoot to plan the rides.
He added: “The south of England was the obvious place to plan the ride because Dover is the port of entry for many refugees, the route sends a very direct message of compassion, and because the letters fit nicely.
“There was an awful lot to consider, both in terms of cycling and logistical constraints such as easy access to overnight accommodation and railway stations.”
The pair also spoke about challenges they have faced, such as suffering from excruciating knee pain, despite being experienced riders.
They said: “It takes a lot of mental as well as physical energy to keep going day after day after day.
“The compensations are being able to eat as much as we like and, of course, the incredibly generous donations from people back home.”
If people are interested in taking part in the challenge, they can carry out the ride on their own or with their friends.
Thighs Of Steel send participants the routes and they can ride wherever they want and at their own pace.
Keen cyclists can also join the team at Thighs Of Steel to spell out any of the welcome letters over September 5-18: https://www.thighsofsteel.com/worldrecord.html
The donation link can be found here: donate.chooselove.org/supporters/lets-spell-it-out/1023/