If you're looking for the unlikely combination of a short, easy approach, moderate trad routes, and no crowds, Buffalo Boulder will make you happy (for an hour or so).
Although it is right off the Loop Trail just a couple minutes from the Loop Trail Boulder and 20-30 minutes from the trailhead, Buffalo Boulder, apparently named for its resemblance to a buffalo lying in the grass (in the picture below, the resemblance is there), is not in either Enchanted Rock guidebook currently in print and is not on Mountain Project and sees little climbing traffic. In fact, it is likely that more hikers reach the "summit" than climbers do since there is an easy walkup on a low-angle slab.
In an out-of-print guidebook called Little Dome Driver, Buffalo Boulder is a bouldering destination, and there are several bouldering problems listed. Two of those problems are long enough and featured enough to go as trad routes, and this page will focus on them.
Don't get too excited, though. Each route is only 25-30', the easier one is quite easy but on very suspect rock, and the harder one is only tough for the first 10' or so before yielding to a very easy finish.
But it's a place to plug some gear and not have to worry about standing in line.
Park in the campground and take the Loop Trail, which starts at the circle at the end of the road.
Hike 20-30 minutes until you see the formation on your right.
Right Leg, 5.5-- The 5.5 is my suggestion; my son thought it was easier. In Little Dome Driver, this one has a V0- grade. It starts as a crack and then becomes a huge flake. Although the flake can take big gear up to a #6 BD cam, you wouldn't want to fall on a cam in the flake. Anchoring is a little tricky. Up top, there is a single old Star Drive bolt with a thin hanger. Because I did not really trust it, I had my son, who led the route first, just walk off. Then I pulled the rope, led the route, put a locker on the bolt, and downclimbed the route. I've been told that you can make a long TR anchor off flakes way back, but that's a lot of extra gear to carry for such short routes.
Left Leg, 5.9-- LDD gives this a V0 grade, which roughly equates to 5.9, though I felt this one felt more in line with 5.8 cracks at Enchanted Rock. But there are fun jams or liebacks while they last, and then the climbing becomes very easy. Anchors? Again, I had my son walk off and then I re-led the route. After leading it, I cloved off the bolt mentioned above and belayed off my harness as my son cleaned. You could build a gear anchor in crumbly rock just below the topout, hope something holds or the climber doesn't fall, and then top out and walk off.
There is a $7 daily entrance fee per person.
All year. Summer mornings are shaded here; later, it turns into an oven.
The park has a campground and also allows primitive camping (backpacking) in designated zones. Reservations are strongly recommended. See the park website.