I think you might do well with the "100 Adventures To Take Your Wife and Child On". There are many adventure type books out there (none as good as your's will be, of course!), but most of us married-with-kids types will pass them up as we'll automatically decide its not relevant to us (and the lucky few without kids may already have bought the other books!).

Selling "the dream" to people with kids is something few try, and it's a very large market.