You definitely also want to see if the little orange (I think, or is it red?) plastic clip is broken that connects the key lock mechanism to the rod that comes up from the door opening mechanism. If so, you may be able to replace it without removing any other pieces.
I'm actually half way inside my door, as well, but for a different reason. The rod that pushes down to open the door from the outside has broken off inside the mechanism and thus doesn't always engage. I have replaced the plastic connecting clip to the door handle twice already. Makes me want to suggest your check the other clip as I mentioned, above. Someone said Lexus made it the weak link to reduce breakins.
I have already picked up 2 new bolts from the dealer for the window guides because I have ruined the phillips head on the one at the bottom of the door. Lexus did not ever want these removed! I'm going to try this weekend to loosen the bottom bolt and work the entire door mechanism out from behind the window guide without removing the window. I'll let you know how it goes if you're interested.
Djones
95 SC400
190k