Investing in land is good if you can find some good deals and the location is good. I would look little outside of kathmandu valley because after 5-10 years people will definitely look something outside of valley.
Investing in stocks in US is also very risky and don't forget for the short term gains you pay good tax also. And holding long term is always risky in this market. I would rather put money in real estate rather than putting in stocks.

Yes you have to have someone to look after Land in Nepal. I have heard stories of people occupying some one else's land and building a house there.

I don't see land value crashing in Nepal right now. Worst case scenario price will stay flat but slim chances it'll just crash.... I wouldn't be surprised if the land value doubles again in couple years.... the current price is ridiculous in nepal and i think its too overpriced already but people keep it buying. I don't understand where they get all that money from.