The Port Authority lost 37 officers in the World Trade Center attack.
Steffans, who coaches a rugby team with a FDNY firefighter, said the terrain has been difficult at times, especially in the elevations. "I'm with some phenomenal athletes. I'm really happy to be involved in this."
He also said the encouragement of his teammates and strangers along the route have kept the spirit alive.
Wills said firefighters and police officers really are similar. "We do different jobs. But, we're dedicated to serving our communities. People say we're crazy for racing toward gunfire. And, they say firefighters are crazy for racing into burning buildings."
The two said it was special to run down the Vegas strip while "God Bless the USA" was played.
Footage from their run was featured on the ceiling above Vegas' famous Freemont Street, and accompanying music "Eye of the Tiger" gave the team an extra boost.
A fifth generation Melbourne firefighter, Rachel Cowling is the only woman participating.
"My dad (a firefighter) came home after his night shift, and told us about what happened in New York City. My dad never cries."
Cowling, one of 59 women in the 1,700 member department, said she's honored to represent her country in the memory run.
She spoke of her grief for the families of those who perished in the terrorist attacks. When the hills get tough, she thinks of their sacrifices and losses.
"I'm looking forward to running across the bridge into New York City on Sept. 11. My father, mother and grandma will be waiting. My dad will probably cry again."
Chicago Capt. Pat Maloney has made a lifetime of friendships these past few weeks. He spoke proudly of the outpouring of support in his hometown when the team arrived.
But, it wasn't just the local turnout that moved him. "In firehouses across the United States, we've been welcomed. We've done laundry, slept in their beds and eaten at their tables. I'm more proud than ever to be a firefighter."
Upon hearing about why the international team was running across the country, many restaurant owners refused to take their money, saying providing a hot meal was the least they could do.
For James Dowdell, the run is especially important. The FDNY firefighter lost his father, Kevin, on Sept. 11.