To seriously challenge defending titleholder Tim Wilding, also from Taupo, Rhodes knows he must put time on his younger rival out of the water, attempt to minimise his losses on the bike and then power home on the run.
"A race like this is probably a bit harder for me in that I don't get as much time on my mountain bike as I would like," said Rhodes, 35. "It is more of a fun event for me than the Ironman but if I did win, I would probably go to the World Championships as they are in Hawaii a couple of weeks after the Ironman."
Wilding will be hard to beat.
After taking the 18-24-year-old age group title two years ago - in a race won by Hamish Carter who went on to claim the world title - Wilding stepped up to score outright honours in Rotorua last year.
Given his undoubted skill and strength on his mountain bike - he is the national uphill champion - he will back that to get him home and show he can be a genuine contender internationally.
Terenzo Bozzone will also have a point to prove after missing Olympic selection for the triathlon.
There is a familiar look to the women's field, with two two-time champions, Gina Ferguson and Sonia Foote, both hoping for a third title.
Like Rhodes, defending champion Gina Ferguson has made her name in Ironman but has successfully crossed the boundaries in the past two years to add the Xterra titles to her impressive haul.
Beaten by nearly six minutes when claiming silver last year, Sonia Foote will put her local knowledge to the test again as she seeks to bounce back to the winning form she showed in 2004-2005. Like Wilding, her strength is on the bike.
Outside the usual suspects, Monique Avery (Rotorua) and Susie Wood (Nelson) promise to mount a decent challenge having won their respective (18-24 years/30-34 years) age groups at last year's World Xterra Championships.
To underline their good form, Wood won the women's race and Avery the 16-19 years grade at last weekend's Xterra Australia in Victoria.
* XTERRA WIN 'UNFORGETTABLE', SAYS CARTER
Hamish Carter reckons the 2006 World Xterra Championship he won in Maui, Hawaii, is up there with the hardest races he ever contested.
The 2004 Athens Olympic triathlon gold medallist said he "really grovelled" in taking the off-road title but nevertheless rated Xterra as a fun event and a worthy break away for the tough, disciplined training rigours triathlon demanded.
"I used Xterra as a bit of variety in my training. It is much better to be hit by a tree than a car.
"The World Championship was my last race as a pro and I was probably not in top shape but it was a race I'll never forget ...
"The New Zealand Xterra is not a hard race and not that big internationally but the World Championships are really intense even if still a couple of notches down from ITU races."
Carter will be in Beijing in August as part of the team's support network.