tall and getting older, need comfortable ride

Three that are a little larger than mid-size, but they are quieter and smoother-riding than truly mid-size sedans:

Kia Cadenza (2014 only)

Chevrolet Impala (2014 only)

Chrysler 300 (2012 or newer, fairly efficient with V6 and 8-speed automatic)

You might also thoroughly test drive a 2011 or newer Hyundai Genesis to see if the ride feels good to you. The ride of this one varies by road type--very good on some, a little busy on others. Fuel efficiency is just okay.

Sometimes, you overlook the most obvious. Late model Camry's and Accords are really big inside and the Camry has a more comfortable ride than most other. The Altima gets incredable fuel economy and is still comfortable. If you want a big cruiser with fuel economy being less important, a 2-3 year old Avalon is very big and almost lexus inside while keeping in the budget.

Among full-size or 'near' full-size sedans, the Hyundai Azera is often overlooked. But in my experience, it's a lot of car for the money and feels like an entry-level luxury sedan on the road.

The Chevrolet Impala is also very impressive.