My granddaughter Bonnie turned 3 in February... and has outgrown the front-mounted baby seat that she's ridden in since early on. So - we have graduated her to the Tag-A-Long bike. (Or "choo choo bike" as she sometimes calls it.)
It was stored for a couple years where it was exposed to the weather, so I had a couple of rusted-up pedals to replace. I lubed the chain, set the seat height as low as it will go, rotated the handlebars backward a bit... and we're good. Oh! I also added a handlebar basket, because she loves to collect stuff to bring home.
On our first ride, Bonnie was pretty excited. "I can pedal! I can pedal!"
The view probably isn't as good as it was before... but she can pedal. (You know what they say about the sled-dog view: "Unless you're the lead dog, the view never changes." I imagine her old grandpa partially blocks the forward view.)
We've probably ridden 30 or 40 miles using the Tag-A-Long at this point. I'm still frequently admonishing her to "Hold on!" - much more important, now that she's no longer surrounded by bucket-seat and grandpa arms. But so far she's done fine, including 20-mph rides down the hill.
The "I can pedal!" dynamic introduced a minor problem on our most recent ride.
Her bike has a freewheel - she contributes to forward motion when she pedals forward, but spins freely when she pedals backwards. And she's discovered that pedaling backwards is less effort, so that's what she does most of the time. So... we were riding along, me pedaling forward and her backwards, and I heard a "klunk" as something fell and hit the ground. It was a pedal. Her constant backwards-pedaling had gradually unscrewed it, and it fell off the crank. (I obviously didn't tighten it up adequately when I installed it.) I screwed it back in by hand, and finger-tightened it. I tried to explain to her... "Pedal the other way, Bonnie!" She tried to somehow cross up her feet, so her left foot turned the right pedal and vice versa. (Dang! I love young kids! They are learning everything from scratch, and it's joyful to be part of that!) I obviously didn't explain adequately... and before we got home, the pedal had hit the ground one more time... and was about halfway unscrewed a third time, when we rolled up the driveway. I tightened it - hopefully it won't be a problem on future rides.