OK, job is done. :thumbsup: There was no need to take out the console, take apart the dash, etc. I don't know if it makes any difference in the configuration of the dash but my car is a '95 XLS. All I needed to do was slide the ashtray all the way out of its tracks, then I had easy access to the lighter. I did a search on this forum and found some previous posts that really helped.
Basically, here's the process. In order to get the ashtray all the way out, first you need to slide it out to its stops and take notice of where those stops are on either side of the ashtray. Then insert a flat-bladed screwdriver into the space between one side of the ashtray and the area around the stop on that side, and pry it (being careful to not crack the plastic) to create a bigger opening. While you do this, pull on the ashtray so that it slides past the stop on that side. Then repeat on the other side of the ashtray. Presto, it comes right out! At this point you'll see how the lighter receptacle is held in place and how easy it is to remove from the ashtray.
Attached to the back of the receptacle are the two wires going to the lighter itself, plus a small light. Remove the light socket by turning it slightly and pulling it out. Remove the very small nut that holds the two wires to the back of the receptacle.
After that, follow the advice from post #6 in this thread, about removing the small bronze washer:
http://www.toyotanation.com/forum/showthread.php?t=334579&highlight=cigarette+lighter
For some reason, by simply removing that washer the lighter receptacle has power again! I guess the conclusion of the poster in the above thread is correct, that it loses conductivity over time.
In any case, I have to take another long drive down to an unfamiliar area of Newport Beach today and it'll be a pleasure to have the GPS working again! :chug: