Willis has a more acute appreciation of the history and tradition of his sport than perhaps many modern-day athletes.
And it is that that has brought him back to Cooks Gardens.
"Peter Snell is, of course, the reason we are here ... to follow in his footsteps. We wouldn't be doing this race if it wasn't for what he did 50 years ago."
On January 27, 1962, Snell - an Olympic gold medallist over 800 metres in Rome in 1960 - stepped out at Wanganui with the aim of being the first man to run a sub four-minute mile in New Zealand.
He surpassed that ambition gloriously, running 3 minutes 54.4 seconds to break Aussie Herb Elliott's world record.
"About two years ago people started talking about that historic occasion coming up, and there was never a chance that I wouldn't be a part of it," said Willis.
"It's a special privilege to mark that event - there's no way I couldn't be running.
"I've had a fair bit to do with Peter Snell over the years and he's always been very supportive, he's always been behind my career."
The New Zealand 1500m record-holder at 3:31.79 and the man with the fastest mile time at Cooks - 3:52.75 in 2006 - Willis admits: "We are the early stages of training for 2012 - we won't be able to do full justice to Peter Snell's incredible performance."
Hoping for a pace of 2.59 to 3 minutes through threequarters, Willis said it would then be a case of seeing what kind of kick he had in the last lap.
"That last lap will hurt like anything for all of us, but that should make it entertaining to watch.
"It's anyone's race ... we are all very unsure of our racing form."
Willis has run 3:50.66 for the mile, while Leer can offer 3:56.63, Bethke 3:57.34 and Emanuel 3:57.62. Willis sees Wellington's in-form Hamish Carson as another threat.
Based in Michigan in the United States for the past 10 years, Willis has a strong affinity with the Wanganui track."I've raced at Cooks many times - I used to go there from Lower Hutt three or four times a year as a kid."
As a 17-year-old he broke the NZ junior record there in 2001. "That really opened a huge amount of doors for me."
Tomorrow, Willis will head back to the Hutt Valley - perhaps after a gentle run round Virginia Lake - and return to his three-month Kiwi summer preparation stint.
He will run in the NZ championships in March but, of course, London is never far from his thoughts.
"The Olympics could be fast, it could be slow, but you need still need that fitness to be able to kick at the end. You need to be in shape to run 3.29 to 3.30 to win, and 3.32 to get a medal."
Despite his silver medal, Willis doesn't feel too much pressure from the Kiwi public.
"People have short memories and I haven't performed up to the level of Beijing in last year, so I don't think there is much expectation for me at the Olympics.
"But, of course, I have my own expectations."