I'm pleased to report that my extended warranty works as I hoped.
Mid December my heater stopped working. I called Kevin Spillane at Toyota Corp. and he coordinated with my local Toyota dealership (in Austin, Tx) to diagnose my car. Basically, they needed someone from Toyota to follow their test procedures to officially document the problem. Once that was confirmed, they were able to open up a case. Unfortunately for me, Toyota corporate was closed between Christmas and Jan 6th, so the information just sat there. Also, temperatures dropped into the low 30s, so I'm glad I the seat heaters still worked. When I was able to finally talk to Kevin again, he was working on the logistics of helping me out. 1)Car is out of state and only EV trained technicians can perform the work, so he needed to find someone. 2)The car is out of standard warranty (42k miles), but thankfully I purchased the premium 6yr/125k extended warranty through Toyota Financial Services (TFS). However, TFS is a separate division from Toyota Motors so Kevin had to make sure that TFS would cover the (perhaps elevated) expense of the parts and labor costs due to the out of state nature. 3) Texas and surrounding states is serviced by Gulf States Toyota which is the second largest franchise dealer of Toyota vehicles in the US (13% of all Toyotas!) http://en.wikipedia.org/wiki/Gulf_States_Toyota_Distributors
Toyota corporate would have to work with them because the service would take place in their territory and they are privately held.
So after a month of driving around the car without a heater, Kevin calls to say he's worked through all the issues and everything will be covered. Yahoo! They will even fly out an engineer to perform the work. The bad news is that the part is back ordered (no surprise after reading this list) and worse, he has no information with regard to lead time from Tesla. I told him I was probably 20th in line according to this group. He said he would call me as soon as he had an ETA of the part.
So, the moral of the story is that buying the extended warranty really does protect you from EV part failures, even out of state. You must be patient though with the procedures.
Since the manual recommends a battery coolant flush at 40k miles, I've put in a request to Kevin to see if the engineer can also preform that scheduled maintenance while he's working on my car, as I want to keep it up and running trouble free as long as possible. Of course I offered to pay for his time and even offered to supply the G48 coolant (supplied from the local BMW or Tesla service center) if that would help. Hopefully, I can get it done.