My 10 and 7 year old daughters and I biked this (the 7 year old has a one speed and did fine - she is a fairly athletic soccer player though).
The scenery was pretty and the river has been made more interesting by the past summer's flooding. The trail is excellent, although there were some spots where my 7 year old had to get off and walk her bike.
We saw a herd of deer and made it all the way to the top of the dam at Lake Georgetown. It gave the girls a great feeling of acomplishment. The downhill ride back takes about half the time going out.