From the Chautauqua parking lot take the Chautauqua Trail to its intersection with the Bluebell-Baird Trail (0.6 mi). Continue past the intersection on the trail that provides climbing access to the first three Flatirons. The trail soon forks. Take the left branch, which is marked as leading to the Third Flatiron, but first goes along the base of the Second. Soon after crossing a talus slope, the trail widens and deposits you at the lowest point of the Second Flatiron. That is where Freeway starts.
The route follows the evident ridge that crosses the east face of the Second Flatiron diagonally, tending right and reaching the north ridge below the summit block. Freeway skirts the Pullman Car and does not reach its summit.
From the foot of the flatiron, go up straight for about 200 feet until you reach the ridge. Continue along the ridge to a notch about two thirds up the face. This notch is traditionally passed by jumping down (5-6 feet) on the continuation of the ridge.
Past the notch, climb a slab until you reach the north ridge, from which you can look down and see the trail that follows the gully between the first two flatirons. Do not try to descend here. Continue instead along the north ridge until you reach a notch from which you can literally walk off from the face and onto the descent trail. Turn right and follow the trail down to Chautauqua.
The lower part of this route does not follow a well defined line. It is also somewhat tricky and you can easily wander into class 5 territory. Higher up, Freeway is very logical, not difficult, but quite continuous: A great route for its level of difficulty. The total length is about 800 feet according to Roach.
Experienced climbers often ascend the Freeway unroped. The route should not be underestimated, though. As a rule of thumb, class 3 and 4 routes on the Flatirons are more technically challenging than routes of the same rating in, say, RMNP or IPW. The sandstone slabs have a way of luring the inexperienced into spots from which both progress and retreat suddenly appear problematic.
If you do bring a rope, keep in mind that the rock is rather compact and does not offer many opportunities to place protection. A light rack with small and medium cams and a few slings to hitch around trees is probably all you will need.
This route is described in Gerry Roach's Flatiron Classics, Richard Rossiter's Rock Climbing the Flatirons, and Mountain Project.