Thanks for starting this thread as I have the same questions.
i use a Chariot cougar 2 for my two kids,2 and 4. The trailer fine for my two year old but the four year old gets bored in the trailer and not really involved in the ride which restricts how far we go. So next year we are looking for an used tag a long.
I be interested to hear know other people got Their children started on the Tag a long and any recommendations on what I should look for.