the trick is to go in summer. It is difficult predicting the weather in Europe these days but it's generally more settled than here. River boats tend to be much smaller than ocean cruisers (they have to fit through locks and under bridges), so they don't have the same scale of entertainment, though I think one or two have pools. It's more about relaxing and enjoying the scenery. Most cabins have balconies, though they're often more like French windows without room to actually sit on them.