It is on my list to. I spent several months in Nepal trekking, wildlife viewing, rafting and the like. I wanted to go but the permit was too expensive for me at the time. My father just spent two weeks there and loved it. The locals don't hassle you, it is beautiful, people still live like they did hundreds of years ago. Tibet supposedly felt the same before the invasion.
Dad did say it is changing though. Modern life is creeping in. I would suggest you go sooner rather than later. You don't want to go after it feels like every tourist spot in Asia.