Any family friendly bike routes in Central MA?

Since I'm a bit north of you, I'm not familiar with the roads down in your area, but what I usually search for is something that has a decent shoulder width or an actual "breakdown lane" to it.  Good roads up in this area (Templeton - Gardner) are Rt. 32 south of Athol down through Petersham, Rt. 122 from Barre up towards Athol, and Rt. 68 from Gardner south to Hubbardston.  The same road from Hubbardston south to Holden is not bad, though it gets a bit more traffic and the section north of Holden is in need of repair.  Roads up here to stay away from are ones like Rt. 140 from the junction of I-190 north to Mt. Wachusett area.  It has no shoulder and heavier traffic and is definitely not recommended for what you want to do.

I like the Cape Cod Rail Trail OFF season or very early (by 6ish) in season, otherwise there are too many walkers, kids and dogs to ride safely . I actually saw a lady pulling her child on a bike with a rope attached...VERY scary. I live south of Worcester and I dont know of any "family friendly areas". There is the East Bay Bike path in Providence. It goes to Bristol and is about 20 miles round trip. Its not as crowded as the Cape. Weekends are a little more populated, but again, kids dogs and walkers are always an issue.

Try this map: http://bit.ly/cZE8IX -- the green lines are bike trails. Note that some of them are mountain bike trails. There is a paved bike trail near Woonsocket, RI which could work for you - flat, and kid friendly: http://www.beginnertriathlete.com/discussion/training/map.asp?routeid=122868

Apart from the Cape Cod Rail Trail, there's the Cape Cod Canal bike trail, and the Shining Sea Bike Trail from N. Falmouth down to Woods Hole. Both of those are nice too... but busy in the summer (don't know anywhere that isn't)

Cape Cod Canal: http://www.mhd.state.ma.us/downloads/maps/bikes/canal.pdf
Sea to Shining Sea path: http://www.capecodonline.com/apps/pbcs.dll/article?AID=/20090613/NEWS/906130315 (make sure you get a NEW map which starts in North Falmouth, not Falmouth)... I really like this path but it's best at sunrise or when it's raining... not so great when busy.

Might also check this meetup group: http://bike.meetup.com/235//>
Even if you don't do any rides with them, they might have some ideas. They actually ride kinda slow (and that's coming from me, so you know it's WAY slow for you).

Thanks for the suggestions everyone! I'll be checking a lot of these links out!