All About River also gives you the ratings on rapids, so you can determine their difficulty.
Many of the rivers are a little low right now for floating - great time for wading though. We will begin to see the flows increasing in April. The Arkansas is a great river to run, but check out the different stretches and their ratings as there are some tough rapids in various stretches. There are a lot of great stretches on the Colorado river so check these out on the site.