right now we drag her around in a burly trailer on our tandem. but she is not even 4 and can ride the smallest bike trek sells. she is not even 30 pounds yet. her bike has 12" wheels that she rides like a champ.
thought about this guy with a donor bike but there is not enough seat post above our back rack.
https://www.amazon.com/gp/product/B0...1GJZM3EQ&psc=1
or this guy Burt its getting expensive.
https://www.amazon.com/FollowMe-Tand...0GGGFVPGWB35H9