I wanted to kayak in Nepal and was hard-pressed to find any resources. This book, along with Lonely Planet Nepal helped me to decide on a river trip. I ended up doing 5-6 days, guided, on the Seti River, and it was FANTASTIC!!! The rapid information is accurate as is the sesonal information. Like I said, there aren't many books on this topic, and this is the best one I found.
One thing I wish this book had told me is that, if you're going to kayak in Nepal, take nose plugs since you can't get them there. The last thing you want to do is ingest river water/runoff when you flip. The water isn't nasty, but you can't see giardia either. However, you can see people bathing in the river at the put-in point. Ha! I just love 3rd world countries!
I also recommend the Seti River trip for adventerous beginner kayakers. You start out with small rapids and by the end of the trip they get progressively harder where you're doing class IV. The water is also warmer than any other river because of the natural springs that feed into it, which is really nice if you're a beginner since you'll spend a lot of time in the water.
River trips in Nepal are amazing because you start to get off the beaten path and see villages that haven't been inundated with tourists. If you'd like more info, I posted Nepal kayaking pics and info at restyoursoul . you know what. If you take a river trip in Nepal, you'll absolutely love it. Did I mention that it's very cheap too? I think we paid $200 each for our 5 day trip with 2 people and 3 guides, which is absolutely unheard of.