I just completed this job and want to say that this post was pretty darn helpful. Here are some additional tips to make this go smoothly.
You will need 10mm and 12 mm socket for most of the bolts. You will need a deep 14 mm socket to drop the steering column (more on this later).
Slide the power seat all the way to the back to give yourself room before you disconnect the battery.
I picked up the SCLA from the local Toyata dealer who had a 25% off parts coupon. It ended up being cheaper than the lowest internet dealer that I could find. I bought the 2 cap screw bolts from Home Depot.
Be sure to remove the 4 screws holding in the hood release and fuel door release handles - lift the handles and you will see them. That will allow you to completely remove the plastic panel.
Behind the plastic panel is a steel panel that needs to be removed (4 x 12mm) and then you will see the steel plate attached to the bottom the steering column.
Remove the black plastic duct that runs underneath the steering column. There is a single screw that holds it in place, remove the screw then wiggle the duct out.
You do not need any special angle drills nor do you have to remove the entire steering column. Simply drop it. This is very easy and will save you a lot of trouble. Take a look at the base of the steering column and turn the steering wheel so that the u-joint at the bottom is positioned such that the column can pivot straight down. Then remove the 4 nuts holding the steering column up (using the deep 14mm socket). The steering column will then pivot on the U-joint with the steering wheel resting on the drivers seat. I was then easily able to use a regular cordless drill and regular length bits on the bolts.
Before drilling, note that there is another bolt on the top of the SCLA. Note how it is all the way in and flush. The bolt is actually a pin that aligns the various parts of the steering column and lock assembly. You will need to make sure that it goes back in flush.
Also note that you will be creating a lot of little metal shavings. These shavings can interfere or damage other gears that are in the column. Do what you can to keep the shavings out of the other areas.
Make sure your drill bits are nice and sharp, and you will be able to drill out the two bolts pretty quickly. When I felt that I had drilled enough, I inserted a screwdriver into the drilled out bolt and used a hammer to tap on it until the bolt head broke and the SCLA dislodged.
When removing the electronics on the REAR of the SCLA, note that it is keyed and can only go back on if the ignition is turned just right. The same goes for the key cylinder. Insert a pair of needle nose pliers into the SCLA to turn the blade to the position that is required. HOWEVER, be aware that if the position is off by 180 degrees, then the SCLA will lock at the wrong time - that is that the steering column will not lock when the ignition is off and WILL lock when the ignition is on. I found this out later.
Attaching the new SCLA was the most frustrating part. The thingy that the SCLA bolts up to has some springs in it that push it away from the steering column, putting it just out of reach of the 20mm bolts. I wonder if slightly longer bolts (25mm?) might have been easier to use. Also keep in mind the alignment of steering column for the bolt on the top of the SCLA as well.
Put the steering column back on, reattach the battery and start her up. Turn the steering wheel to opposite ends to check that it doesn't catch/lock when the ignition is on. Drive around the block a few times to be sure. If the steering wheel does lock when it is not supposed to then you need to turn the blade in SCLA by 180 degrees. It is a tight fit, but you can do this without dropping the steering column. Remove the electronics from the rear of the SCLA and remove the key cylinder. Use your needle nose pliers to reach into the SCLA and turn the blade 180 degrees, then put everything back together. Take it for another test drive to verify that the locking mechanism is working properly.
If all is good, then close up the patient and go get a beer.
It took me about 4 to 5 hours total. That includes a lot of time trying to figure out the best way to reach the bolts, trying to get the new SCLA back on, and figuring out the reversed column lock situation. But knowing what I know now, the job should take about half of that time.
And from now on, make sure you turn the steering wheel to relieve any pressure off the steering wheel lock before turning the ignition.