Advice needed about cycling with young children

[maillotpois]

That's one of the coolest bike set ups I've ever seen! Did you design the upper pedal thing yourself, or can you get those?

That's called a "kidback" or "child stoker kit". They're available several places. We got ours here:
http://www.precisiontandems.com/artkidbackinstall.htm

Sheldon Brown wrote a lot about cycling with kids:

http://www.sheldonbrown.com/tandkids.html

As Geonz said, we've put a lot of miles on our bike with the PP. I don't have much to add, though, coming to the party late (we still don't have power or internet access). I will say the PP is definitely a fair weather rider - too cold or hot or rainy and it's no fun. It' all about being fun.