Trap Dike is a semi-technical ascent route on Mt Colden, the "historic mountaineering route", according to https://www.adirondackexplorer.org/stories/trapdike
Car-to-car specs are about 12 miles and 2800' of gain and loss, with most of the gain on one 30-40 degree scramble on the Dike, and a steep descent on the Arnold Slide. A route map by Phil Maynard is here.
This route starts at Heart Lake, goes up the avalanche lake trail around Avalanche lake, up the Trap Dike, and down the Colden trail to Lake Arnold. From Lake Arnold follow the trail back to Marcy Dam and end where you started at Heart Lake.