On a more serious note, if you do come the way described there are some intereting points along the way.
Wellington has plenty of older historic buildings if that's up your alley, but just outside there are the Wellington Caves and Phosphorus Mine. Definitely worth a visit if you've got the time, both cave and mine tours are quite good. About five minutes down the road is Bell River Estate if you like fortified wines (less so for the kids, but it's a brief stop).
Further afield is Lake Burrendong (actually a massive dam - three times the size of Sydney Harbour) and its Burrendong Botanic Garden and Arboretum. The former is good for a quick swim, the latter for something a bit educational.
Along to Molong, there are rumours of a hat store that has a back wall full of hats left by previous owners upon purchase of a new one - all stapled to the wall because that's the only way to get the trusted hat out of someone's hands out that way. ;) Could catch someone's fancy? More prosaically it has a few wineries situated around town that are worth a visit, but more to keep the adults from throttling the kids.
Getting closer to Boree, about fifteen minutes out of your way is the home of the best cider in Australia (IMO) - Small Acres Cidery. Hmmm... there's dogs to play with for the kids?
Canowindra does have the Age of Fishes Museum. Run by the Australia Museum in Sydney, it's dedicated to the discovery of a very rich local fossil fish find. I'd definitely drop by, but then that's my kind of thing.
I'll defer to jpatokal's comments on Cowra, only to add that the area is well-known for its wines and has plenty of cellar doors open at various times of the week. Kids can stay in the car.
And to end on yet another boozy note (kids, who needs them?), the Young region which includes Boorowa is also known for its wines - so if you've recovered from the previous umpteen stops, why not make one more before Canberra? After all you need to survive a visit to our nation's capital somehow, and not sobering up is a time-honoured tradition by many including our federal politicians.