Brad – Forest Park is fifteen minutes from home and the nearest steep hills are more than an hour away, so I end up there once or twice a week. One thing you might try, if you don’t mind doing repeats… the steepest section of trail I’ve found there starts at the steps on thurman, to aspen, along wildwood, and to the top of birch (1.6mi, 625 feet). The longest climbing section starts at aspen and ends where wildwood levels off (about .78 miles and 540 feet or roughly 692 ft/mi gain).
There is a bit of steepish terrain, but not much, and it takes four round trips to get 6.25 miles and 2160 feet of climb. Not as good as Defiance or Hunchback but a lot better exercise-to-drive time ratio.
If you want steps, Mt Tabor probably has the two longest runs in the area, on the east side and between the reservoirs. That will give you more steep, at the price of a lot of mind numbing repetition.