Hi Mysticl,
This is an indirect reply to your question and just another point of view.
Your training will serve you well on the camino that's for sure, but it's very different from walking uphill for most of the day.There is more involved in that day 1 walk than just going up a mountainside and that is the question of jet lag. Unless you are planning to rest a day or so somewhere after you land in Europe, you MAY find yourself unusually tired from the time difference and flight (planes are so hard on us) that day 1 could be harder than if you were to do the same thing at home.
I strongly suggest that since you're worried about it, you do not tackle the whole walk from SJPP to Roncesvalles is one day unless you have been practicing walking 27 km over hills and dales. It's harder than many people think and easier than others think. But is there a rush? Stopping at Hunto or Orrisson makes for a pleasant evening around a dinner table with people who will soon feel like friends -and takes a big bite out of the long climb. It is still about 17km from Orrisson to Roncesvalles.
In my experience it's better to go a bit slowly at the beginning and build your strength. (I've been over the Route Napolean as it's called 3 times). But hey - I'm old and slow so my way isn't for everyone of course.
Another alternative of course is to back up a bit on the Le Puy route (around Ostabat or Aroue) and walk along the flattish country for a couple of days to get the jet lag out of your system. You'd be much more ready to tackle the mountain after that. Who knows - depending on when you're going, we might even see you there.
Congratulations on all the hard work you've been doing to get this walk working for you!
Buen Camino