Conundrum!

“One pair of jeans takes up an entire pannier, so I’m looking for something a little bit lighter weight.” Wait, hang on a second, one pair of jeans? So out of these two panniers I will be riding with for four weeks, a pair of jeans takes up an entire one?! Crap, I seriously need to start thinking about this, because, clearly, this is going to be an entirely new level of packing light. I hope I don’t need too many warm layers, I don’t think there is going to be room for them!
It’s not that packing light is that hard, it’s just that this next trip is a hodgepodge of different events and climates. First, I’m flying into Heathrow, heading to the Dingley Dell for my cousin Duncan’s wedding and some serious celebrating. Then, my mum, stepdad and I are heading up north to visit some friends, hike some monroes and drink some scotch along the way. Actually, if my stepdad has anything to do with it, we’ll be tasting more scotch than walking miles, which is ok, we’ll make up for it later. From the highlands we fly to Lillehammer, Norway, to visit my godmother Riedan. After a couple days of exploring the land of salted fish and lingonberries, we fly to Geneva, to start our epic bike tour (because the rest of the trip isn’t epic enough) Our plan, so far, is to ride from Garmisch Parten Kirchen, Germany, through Italy, into Switzerland and end in Annecy, France. However, it’s still a little up in the air. The easiest way into Annecy is over the Col de Forclaz. Please, please, please don’t make me ride over this with panniers! It’s a brutal, 8-10%, 8 km climb that even the tour respects as a challenge. Ok, I might suck it up, but only if we can stop for lunch at the top!
Back to my original question, how am I meant to pack for all of this?