He has a box of broken wheels, blisters and hopefully a world record to show for it.
And those dark places he mentioned were not just a metaphor.
He had to return under the cover of darkness to complete the section through the Rimutaka Range.
The police had asked him to cease and desist.
Apparently he was not too popular with some motorists.
There's a surprise.
But the tenacious 28-year-old was not about to have his record-breaking attempt interrupted by the long arm of the law.
He went back when the coast was clear and slogged his way up those awful, awful hills. In the dark. The mind boggles.
He has been called everything you can imagine by peevish motorists and has had the odd alarming moment coming downhill.
There is no stopping on a dime. You have to drag your foot behind you, cross your fingers and hold on.
''I'd be going 40 or 50kmh downhill and then, `boof', this happens,'' Baena says, pointing to a box of mutilated wheels.
''I break a lot of wheels.''
Better wheels than bones, right?
''It can be very scary. Sometimes I think this is it, I'm gone, you know.''
Going up is almost as bad. He could walk faster during the really steep climbs. But despite all the challenges, Baena left Dunedin yesterday in great spirits.
If all goes well, he will reach his destination - Bluff - sometime tomorrow evening.
He will have zigzagged 3000km from Cape Reinga and regained the world record for the longest journey on rollerskis.
Frenchman Gerard Proteau broke Baena's 2012 record of 2246km between Oslo in Norway and Stockholm in Sweden with a journey of 2783.4km in June.
Baena, who got his start in the quirky sport as part of a training programme for the more serious business of cross-country skiing, wants the record back and here is the sweet part.
What gets him through those other dark places - the ones which exist only as a nagging doubt in your mind - is his grandmother, Luisa Santana.
She died four years ago but was a tremendous supporter.
She funded his cross-country skiing ambition and when he told her of his dream to rollerski the length of New Zealand, she made him promise to follow through.
''Even though she is not here with us physically, her energy is with me. It is a big importance because I feel like I owe her and that is why I'm doing this.
''It is what we dreamt about. She always encouraged me to keep going during the hardest times and I have faced really hard times here.
''The first two days I was lying in the grass thinking this is really hard. But day by day, step by step, and now we are almost there it feels like double sensation. For one it is like, wow, humans can do really amazing things but you have to really believe.
''The pain in the muscles is so hard, in the night I can't sleep and I have to drink some pills to relax my muscles.''
He started his mission on December 22 and has taken a day off once a week. To complete the journey on schedule he has had to average just over 73km a day.
That has to be worth a cold beer when he gets to Bluff.
