Wider tires, lower pressure. 32mm are decently wide tires, but ones with softer sidewalls may be more comfortable. The Pasela is a good, cheaper, comfortable tire. Soma/Rivendell tires are a bit softer, and Compass/Grand Bois tires are among the softest. The prices go up accordingly.

Here's a handy calculator for tire pressure. It will give you a pressure that is optimized for max comfort. You'll notice that it suggests a lower pressure in the front tire, which makes sense because it carries less of your weight.

Let the tires be your suspension. A suspension fork seems like a good idea, but adds weight and saps some of your pedal effort.

I find Brooks saddles to be the most comfortable. They're expensive, but worth it to me. The B68 is good for casual, upright riding. The B67 is the same saddle with springs, which are nice if you're heavier.

Lastly, consider new hand grips.