My summary of riding the River Road (RR) vs the Katy Trail (KT):

RR: Sometimes it's a separate bike trail, a lot of the time it's riding on the shoulder of the road with traffic whizzing by at 40mph or more. Scenery is constant: river on one side, bluffs on the other.

KT: Hard-packed trail, with relatively little traffic interaction, and only at intersections of trail and road. A rural riding experience: some river, some woods, some farmland, with a mix of small towns.

I'm a real cycling klutz, but I've ridden the KT with 700x25 tires. If it has rained recently you may wish to go a little wider.

I strongly prefer the rural KT riding. I commute through the suburbs most days of the week and ride the narrow suburban roads on the weekends. The KT, while not the ultimate cycling experience, is a welcome break from dealing with vehicles.