The Oak leaf, as mentioned, is more a local path than a destination. That's not to say there isn't some good riding on it and many stretches are lightly used. The eastern portion is probably the most used as it's near downtown and the colleges. As you go around the city parts of it are on city streets and parkway roads. It will also connect you with the New Berlin Trail and ultiamtely the Glacial Drumlin trail. It does not quite connect to the Interurban yet but comes within a mile or 2. Here are some maps that are usually available in the bike shops or contact Dave on the page and he could probably mail one out.

http://city.milwaukee.gov/maps4460.htm