Which Katy Trail are we talking about. The Katy Trail in Missouri can be somewhat bumpy in places. Make sure to not over-inflate your tires. You probably can go with something like 70 psi if your tires are at least 700x32's and you don't weigh more that 215 lbs. Guess how I know.

Also get a good pair of cycling gloves. I like gel gloves that are a little loose as my hands tend to swell up.

You might be able to fink some more comfortable handlebar grips for the bike.

Lots of good info from the above posters.