If you haven't been to Ferryland Lighthouse for a picnic yet, you really should give it a try. The food is fabulous, the hike is good, and the possibility of seeing whales while you dine is a real incentive.
Lighthouse picnics advertises a children's picnic on their web site, but I haven't tried that option myself. If you have, let me know what it was like.
The road to the lighthouse will seem long for little legs, but a good trail model stroller or a child carrier and a strong back can get you there. Leave yourself lots of time to enjoy the walk and you'll have nice tired kids on the way home. A picnic blanket is provided so don't worry about lugging a bunch of gear out there.