Just got back. When i picked up the car, it was still in the airport. When i returned the car, there are orange (similar to construction) signs showing you where to go to return the cars. To drive from the Terminal to the car rental location took me about 5 minutes (i dropped the wife, the kid and all the luggage off first). Definitely not walkable...
Also just to confirm, i did get my rental through steve2 and the rate (with confirmed upgrade) was exactly as expected. (i even stayed an extra 2 days due to the volcano issues in Iceland and was charged for 2 days proportionate to the original quote)