As recommended by one of our stockists, Bicycle Centre Ballarat, here is a great family bike riding trail in Ballarat.
You can break the ride up into different section so depending on how far your kids can ride, this is a great option.
A recommended part is the Gong Gong Reservoir Park - this is a great bushland escape from Ballarat, with native vegetation, picnic areas and walkways. You can ride a short loop within the reserve on a gravel road and do short walks to the reservoir bank.
You can find more great rides in the Ballarat region from this website: http://visitballarat.com.au/things-to-do/cycle-ballarat/scenic-rides.aspx or here: http://visitballarat.com.au/media/1399188/city%20of%20ballarat%20bike%20rides%20v5.pdf
View Yarrowee River Trail Network in a larger map