Sophie Sands, 23, and Emma Rae, 22, will cycle the route over 11 days from Friday in a bid to raise funds for Scottish Adoption and Alzheimer's Research UK.
Miss Sands, of Edinburgh, was adopted from Malaysia when she was a baby and is raising money for Scottish Adoption, while Miss Rae, of Aberdeen, is raising money for Alzheimer's Research in memory of her grandmother.
The former classmates hope to raise £5000 to be split between the two charities.
Miss Sands said: "The main reason behind me doing the challenge is kind of a preparation for me going to Malaysia to try to track down my birth parents.
"At this stage in my life, I'm ready to find out who my parents are and when I started looking into things, I discovered there was a charity called Scottish Adoption who supports people who have been adopted."
The women will be supported by their parents throughout the bike ride.
Miss Sands added: "Both of us have never done anything like this before, we're not really keen cyclists, we're doing it because we want a challenge and we want to raise money for a good cause.
"We've been training a lot and we're physically ready for it, but obviously the reality of cycling five to six hours a day for 11 days could be a lot harder than we expect."
So far, Miss Sands has raised a total of £185, while Miss Rae has raised £1,324.
Anyone looking to donate can do so at mydonate.bt.com/fundraisers/cyclingAA or www.justgiving.com/emma-rae.