You get to know a place better on a bicycle than you do whizzing past it in a car and kids love riding bicycles. Bicycling is something the whole family can participate in. Children that are too young to ride on their own can come along in a child seat or trailer.
Older kids relish the independence of covering the countryside under their own power.
And everybody gets plenty of fresh air and exercise. A bicycling trip may be the solution for your next vacation. And bicycles can be rented just about anywhere, so you might consider a day or two of bicycling at whatever vacation destination you've picked for your next trip. This is a vacation, not the Tour de France. Get an early start, but park the bikes early, too, to give the kids time to play, and yourself some time to relax.