Thanks, Superpug, sounds like a good pirep on the Five Hundred. If I go practical, I'm more interested in the Regal, but that Ford looks easy to install a computer in w/ the big compartment on the dash. A test drive would, of course, be a big deciding factor.
The 500 is a VERY well built automobile. The wife was looking at one and we took one for a test drive. The interior was great except one thing, less hiproom then her old 1997 Taurus. The car is wider, longer and higher than the 1997, but the console is larger.
She ended up getting a Certified Used 2006 Sable for $13,000 (it only had 9,000 miles on it). It was the dealerships loaner (not to mention I've known our Salesman since the 7th grade). What is great about that? The Dealership is a Lincoln/Mercury dealer with the clientèle being well over 40 years of age (meaning not ragged on).
The Regals are nice, I was considering a GS back in 2000.
I currently have this: (this is my car)

The Quality numbers are through the roof on the entire Fusion/Milan/MKZ (formally Zephyr) platform. The majority of the platform is done by Volvo and the FIT and FINISH on my Milan is 2nd to none. I have the 4 cyl and get 30mpg on the freeway. The trunk is ALMOST as large as the 500/Taurus. Superpug1 claims the AWD 500 gets 30+ at 75-80, no way in hell. 25 would be about right in real world conditions.
I'd sincerely recommend you substitute your 500 for the Milan. I have airbags, including the safety curtain. There is room for 5 adults with MORE THAN enough legroom. I live in Michigan, but have been to Portland, Or twice. I am well aware of the "Black ice" you guys get (as our Wedding was in Dec.) and it isn't fun to deal with.