So, how should I do this? Which way? From home, it seems logical to travel from the (presumably cold) Atlantic to the (warm?) Mediterranean. But is that the best way with a loaded touring bike? Are the passes easier one way than the other?

I did a little researching on CGOAB and came up with Scott Anderson's journal of the trip he and Rachael did in 2013 from Girona to Bilbao (https://www.cycleblaze.com/journals/girona2014/). I copied a lot of his route and merged it with the Pyrenees route published in Lonely Planet's Cycling France. I think I read somewhere that the approaches to the cols are easier travelling east to west. I hope so. In any case, I needed to work out something in order to book my flights with enough time between arrival and departure.

I'll be away from home for 32 days--I feel a little guilty leaving my elderly dog for so long. She won't be alone (Al will be home, and most likely one or both of our sons), but she will be 15.

Those 32 days include travel time and an estimated 22 days of riding (including two day trips). Not a lot of extra!