I have tightened the guide bolt and replaced my rack bushings so far. There was improvement from doing these things but the problem remains. I just received a newer style guide and will install that next. After that I'm looking at the column.
Check out the tutorial and documentation reference sticky. It has a link to a very detailed guide on replacing the steering rack guide. That is a common point for slop, so much so that Toyota redesigned it for 01-02, so you could try replacing yours with one from an 01-02 4runner.
Regarding the column, again, this is a very specific fix for a specific problem, not a general front end slop problem. The tutorial and documentation reference sticky has a link to a great thread on that as well. Don't jump to welding the column without taking the 10 seconds to actually diagnose it.
I'll make it easy for you, here's the instructions on how to diagnose play in the column:
Diagnose Your Truck in 10 Seconds:
As Gunny pointed out, you can check to see if your vehicle has this problem simply by reaching under the dash and holding the steering shaft in one hand while slightly turning the steering wheel back and forth with the other hand. The shaft is behind the Lower Left Hand Finish Panel, and you can reach it without having to remove anything. I included a picture of this area in the procedure below. If you detect a small amount of movement between these two locations (you will feel a small knock, or pop), then it is likely that your truck has this problem. I have read many posts where people have replaced entire steering racks only to find that the problem is still there. This quick test will tell you if there is play in the steering system even before reaching the steering rack.
Go here for the link to the pictures:
http://www.toyota-4runner.org/3rd-gen-t4rs/69744-tutorial-documentation-reference.html
Seriously guys, just take the 10 seconds to check this, and come back and tell us if you had play in the column. It's free. That will answer that question once and for all.
I know it is annoying chasing this problem, but like I said before, there are lots of possible contributors. I see a couple of you say you replaced all your joints, and even your rack, but how're your struts? New, old, worn out? For me, the struts were 90% of my wandering on bumps. May not be it for you, but it's very possible.
Also, the article linked in the sticky talks about the viability of the tack welds to break in a crash and still provide the ability of the slip joint to give and not injure the driver as much, but I don't really buy it. A weld strong enough to hold the stress and vibration of the steering column (since there is play, the weld is taking that stress) is probably not going to give with just the weight of your head and shoulders slamming against it. So bottom line, welding your column is disabling a safety features that Toyota obviously went well out of their way to provide (and paid more for), so do it at your own risk.