My wife has a Nissan Sentra. 2012. Rides as smooth as butter. But don't try to take a corner quickly in it. She loved my 2009 Focus SES Coupe. It handled well for what it was and the twisty roads were always fun, but the ride wasn't as smooth as her Nissan. Not that she ever complained. (Why she picked the Nissan is beyond me. It was 100% her choice, I tried to talk her out of it).
I'm a die-hard Ford guy. My dad had a 1946 Ford pickup with a transplanted 351 Cleveland with the racing heads, a transplanted auto-trans and drive train, but the body was 100% stock. (no real
suspension in those to speak of (leaf springs on the back, that was about it). So every time you started it up, it registered about a 3.5 on the Richter scale). My first car was a 1957 4-door Ford Fairlane. Smooth ride and a tank, column shifter... I'd say check out the Fusion and stay away from low profile tires/rims. They will make the ride harder. I hate Microsoft but I love Sync in these cars. Hands free calling is so easy. In my wife's car you have to jump through so many hoops to make a call. It's terrible.
What I'm saying is. If you have to give up the Mustang, at least give the Fusion and the Taurus a chance before going with a Honda. quality wise, Honda is no better or worse than Ford these days. All the manufacturers are about the same except possibly GM, which still makes crappy interior components. The Chevy Cobalt my ex-wife insisted on had an interior that literally started falling apart within 6 months. The automatic gear shift button FELL off, and Chevy said all they could do was superglue it back on because they had no other way to fix it. Driving down the road, the dome light cover fell off and hit me on the head (smooth road too). They super glued that too. Then had a bitch of a time and tore up the headliner trying to change a bulb a month later.
And the last time I sat in an Accord with leather seats, the seats were so damned hard my ass was hurting after a 20 minute test drive that I took last year.
My sister in law bought a Fusion after taking a ride in my Focus when she came out to visit. She loves it, and the roads where she lives in California probably aren't much better than where you are located. In my opinion the Fusion will give you a more comfortable ride, but still be fun to drive. It consistently receives great reviews and looks good as well.
I have no experience with the whole MyTouch, because I've heard the stories and stayed away from it. May not be an option in 2015. So start shopping now.
Ford has come a long way since the 80's and 90's.
That's my suggestion.