I'm planning to do the Katy with my family this summer as well. We haven't set the date but wify knows I'll be really cranky if we don't do it this summer. We still have to see if our 7 year old son will be riding his own 7-speed bike or ride on the trail-along. Depending on that our 4 year old daughter might upgrade from the trailer to the trail-along. Of course the distance we'll ride will be quite a bit different depending if our son will ride on his own.
BTW, I much rather pull the trailer than the adams trail-along bike since it's so floppy. That's probably where the Burley Piccolo recommendation comes from. But I'm sure a tandem would be the nicest for touring with kids.
Maybe we'll see you out on the trail.