with respect, you are prime in the middle of the category:
too little too late.
forget jogging; it is the worst exercise you can ever do for anything ever.
cycling is good, but is a war of attrition
the gym is my preference, but all year round, not the week before.
if you go to the gym and try to hustle some development, you will probably injure something and spend you time in the mountains sat on yer arse.
my advice... do the sitting against the wall with knees at a right angle, about 10 times a day (5 in the morning, 5 in the arvo) each for as long as you can endure. stretch before and
after these exercises and most importantly
stretch after and before your day on the hill.
and next year, use some bloody foresight!