The Direct (Standard) East Face route on the First Flatiron is about the longest slab route you can get in the Flatirons. Rossitter clocks it at ten pitches, though this may vary by rope length and leader's choice. I've personally done it in nine pitches with a 60 meter rope, and two of those pitches were quite short. In any case, it's a long, long climb. None of the pitches are extraordinarily difficult, but it's not a 4th-class scramble with occasional 5th-class sections like the standard route on the Third Flatiron. Each pitch is also a little different from the last, so you'll enjoy the trip immensely!
From Chautauqua, hike the standard approach trail past the Bluebell Shelter following signs for the First Flatiron. The route starts at the lowest point on the rock in a well-developed area of wooden beams and cobble stones. It's hard to miss!
Starting from the lowest point on the rock, climb some very attention-getting slab up a broad, shallow gully aiming for a small tree on the left side. This is doable with a 60 meter rope, but a 50 will come up a little short. There are three bolts in this pitch, but they can be easy to miss. Many people consider this pitch to be the crux of the whole route given the smooth slab, abrupt start, and lack of protection (even from a Flatirons point of view).
Continue from the tree on easier terrain aiming for the middle of the large, chunky bulge above. There is a large flake which can be slung below the bulge and makes a passable anchor.
Surmount the bulge in whatever way seems best. The route through the middle follows a steep, chunky chimney. It's steeper than the slab below, but the holds and protection are good. Bearing right above the steepest part brings you to a good belay stance. Alternatively, continue up the steepest part of the bulge to emerge on top. From here, the Headwall of the upper First is visible.
Climb across the level top of the bulge and up the lower Headwall intersecting a couple of diagonal ledge systems (Fandango and Bakers Way routes). Belay below a large flake in a diagonal channel.
(This is the one I consider to be the crux.) From the belay cave, climb a smooth, steep chute under the left edge of the overhanging flake. Look for holds and protection under the roof on the right and in the flake on the left. Don't fall! Emerge abruptly on the ridge and set up a belay.
From here, you're on the ridge and the route is mostly horizontal. Traverse three separate towers before the final summit tower. In general, the climbing is not difficult, but there is good exposure and a couple of dicey moves. Protection is available, but you have the choice of runout climbing with the potential for long, nasty pendulum falls or ferocious rope drag as you connect-the-dots on the crennellated upper ridge.
to the west from bolts 100' to level ground. Unlike the Third Flatiron, this rappel is straight-forward with a good start and a slightly overhanging finish.
south and east following the well-worn trail between the First and Second Flatirons back past the start of the climb. Marvel at the vertical distance you covered!
A standard Flatiron rack is sufficient here: a set of stopper and medium to largish cams will do the job. Augment this with a supply of long runners, even webbing, to sling boulders and horns. Protection is scanty in the Flatirons and this route is no exception.
A 60m rope is required to reach the first belay tree and for the rappel. 50 meter ropes will neccessitate an intermediate belay or a bit of simul-climbing on the first pitch and will make the rappel much more difficult.
These also come in handy in slinging blocks on the final towers. It is also useful to bring extra clothing as this is a long route and significant weather change can occur. The rock is shaddowed in the afternoon and can get chilly.
Unlike many of the Flatirons, the First is not usually closed for raptor nesting between February and August. Thus it is a popular climb and is crowded even in the 'off' season.