Format sounds familiar....
A widowed park ranger has a blond late-teen son plus a "tween"age son as well. The story really revolves around the family's "unofficial pet" who actually roams wild in the park but likes to stay close to the family (especially the younger son), and helps them whenever trouble arises. Some episodes feature a Germanic-family woman scientist around the park.
In one episode, a man who is a look-alike of the park ranger commits a robbery, thus framing the real ranger for the crime.
I'm talking, of course, about 1964's "Flipper"!!