But the friends were parted by love.
"She met her now-husband by then and her life was taking a different path.
"There was a couple of years gap then I continued on my own in the North Island.
But the North Island leg was not completely alone. Like her friend Kendall, romance found its way into Larissa's life. An old boyfriend, Alex McFarlane, had been keeping tabs on her journey, an easy thing to do when your ex is carrying a GPS tracker on their horse.
"I went overseas, came back and we re-connected," McFarlane said.
"I knew she'd done the South Island trip, so I knew what I was getting into."
Alex loves trail running and every morning scouted any difficult routes, taking photos to show his fiancée.
Larissa is a lot more confident than when she started from Clifton Station. The farm had been chosen as the start to avoid heavy traffic for their 'green' horses.
The bond between rider and horse has grown very strong.
"She is just the best horse, well behaved and sensible, so she's been the perfect partner for me.
"She has become more than half of the team - I don't think I could do this without her.
"She has done incredibly well - she has toughed out the whole thing."
The circumnavigation was completed on April 10 with a warm reception at Clifton Station, attended by friends, family, Hastings Mayor Sandra Hazelhurst and Kendall Waugh, with her new baby.
As well as a personal challenge, the circumnavigation has been a fundraiser
for the Leg-Up Trust, raising $15,000 so far. Sprite will now remain with the charity indefinitely, making a connection with people through equine therapy, while Mueller and McFarlane move to Otago for the next chapter in their lives.
It includes another journey around New Zealand, thanking the many supporters that helped make the circumnavigation a complete success.
Made with funding from