You should be able to un-snap the back plastic panel on the swing-out door. This should give you clearance to get a pair of pliers on the back of the screw and twist it out...

[edit] a plastic pry-tool will help greatly with this. Don't use a screwdriver, unless you want to risk scraping the plastic

 

If you go with the drill method, you can graudually increase the size of the bits until the head falls off. Then switch back to a thinner bit in order to drill the screw shaft from the middle.

A screw tap would also work but might not be necessary for such a small job.

I put antiseize on the bolts when I first screwed them on and have remove them a few times without problem.

 

I've had this problem, not on the RAV, but on other old cars. Luckily I was always able to get to the back of them. I replaced the ones on the RAV with stainless shortly after I got it.

 

Update: I removed the rear doo interior panel tonight. Luckily, I didn't break any clips. There was not much room to work, but I managed to get some small vice grips into the opening and tried twisting the screw out from the back. No luck, the part of the screw that was sticking out snapped off. I went back and finished drilling it out.

Of course since I got a late start, I will have to wait until tomorrow to buy a tap to re-tap the hole. I also plan to buy all new stainless steal screws for all 3 of my vehicles. This has been a lot of trouble that could have been prevented easily for a few bucks. Nearly 30 years of driving and maintaining cars, and I've never had this problem before.

 

When I lived in Minnesota in what then must have been the champion U.S. winter salter of roads, I used nylon screws for my license plates and didn't have any problems removing them when I needed to. They survived even the -40F winter blasts.

 

I was able to buy a tap last night. 6 mm/1.0. First time I've ever used a tap, but it went smoothly. I bought all new stainless steal screws for all 3 of my cars. Got the plate re-installed and snapped the interior panel back on.

I still need to get some anti-seize compound to go on the threads. Maybe this weekend.

I wax my cars about 2-3 times a year. My plan is to remove the tags when I do that and inspect the screws.

This has been a PITA, but it has allowed me to learn a few things. How to drill a screw, tap a new screw hole, remove the door panel... Also learned that I need some better lighting in my garage.

Thanks for all the suggestions.