I have a 2002 SR5 and everything was snap-off. Since you have a 99, I figured it would be similar to mine.
Here's what I did:
Lift the armrest in center console.
Pull the housing from around the handbrake which included the cup holders. (mine was just a black piece that ran from above the handbrake down to the cup holder area)
Then pull out the piece around the shift knob.
Then remove the dash area around the headunit. (easier to snap off from the bottom up)
Hope this helps