But a serious horse accident in November 2002 left her a C6/C7 tetraplegic.
In 2010 she led a group of 25 Catwalk supporters to the Big Apple for the New York Marathon. She enjoyed the event so much that a year later she saw The BIG Cycle adventure in a magazine and thought "that sounds a bit of fun".
The team will start in Lhasa and ride to Kathmandu over the 28 days.
They would be riding about 40km a day and although it might not seem far, the altitude would be the hardest factor, said Ms Williams.
"The doctors are very worried about how the tetras will cope because a lot of our body's functions like lung expansion and even the ability to cough is compromised.
"So what is difficult for an able-bodied person at altitude is compounded for a tetraplegic."
Mary Weston, a friend of Ms Williams, is amazed at her ability to keep going. "It is hard for an able-bodied person to do this event let alone a tetraplegic."
Ms Williams doesn't see it like that.
"Although 75 per cent of my body doesn't work the way I would like it to it doesn't mean you can't do things.
"I think it's really important to use the things that do work, so for me it's my shoulders."
So far the team has undergone a year of extensive training and spent some time testing how they will go in the altitude.
"We have been using a thing called an alto-lab that we got in from the States.
"It is a little machine that creates altitude to see how you will breathe.
"And I will be honest I did not cope that well with it."
Members will be camping half of the time while climbing the Himalayas.
And Ms Williams says wheel chairs and tents are an odd match.
Ms Williams did not know the two other tetras before they decided to take part in the challenge and said she was excited to endure the journey with them.
"Before my accident it was all about me and what I was doing with my horses.
"Now it's about what we do as a team and the rewards are enormous. You make incredible friends for life as you go through the experiences."
Ms Weston described her friend as "very charming, caring and very determined with a great passion for doing things".
"She was a very good rider and always takes life head on. It's great she has found a way to channel her energy."
Ms Williams' husband, Sam, a stud farm owner, will be completing the trip with her.
To support the cause the website is www.fundraiseonline.co.nz/TheBIGCycle