That is SO cool! What a great plan

I don't much about bike touring, but we've hiked and skied and camped a lot with our now 12-year old. Our experience is he doesn't need or like specific "training", but we make sure he's been active daily and on his feet a lot in the weeks in advance. My guess is that with biking it's easy to adjust the intensity so that you can take it easy to begin with, but comfort on the bike is really important to get right from the start. How about lots of short evening trips just the two of you, just so she gets used to sitting on a bike daily?

I think you'll really enjoy having a trailer. We used one a lot when our son was small, and it was a godsend for hauling stuff.