Tourism and Adventure sports in Himalayas

It will be midsummer there. There are beaches but nobody gives a crap about what you look like in a swimsuit. It is very relaxed and there is a lot to do.
You could do the Bay of Islands for beaches, sailing, big game fishing or scuba diving.
Or Auckland is good for a city vacation. City stuff, go to the museum and aquarium, go up the volcanoes, out on the ferries to the vineyards on Waiheke Island or the bird sanctuary on Tiritiri Island, out to the west coast side for big surf, scenery and solitude.
Rotorua/Waitomo Caves/Taupo loop for adventure sports and the geothermal tourism stuff, hiking, or trout fishing

I'd go for Peru, myself. Chile next. But definitely, need more details to give any helpful input. Argentina was less interesting to me than I expected -- I think Buenos Aires is probably pretty great if you want a city experience, but then I'm not sure how much there is for you outside of that. (Having said that, I haven't been to Bariloche, and would still plan to. But only as a side to a mostly-Chile expedition.) Costa Rica is great, but also has a seriously tourism-driven economy, and is really best if you want to do adventure tours/sports or just completely relax. Peru and Chile I like because there are just lots of options, at least as long as you don't crave a metropolis and want more culture, outdoors, whatever

Nepal is a land of unparalleled scenic beauty located within one of the most diverse geographical areas on earth. Nestled high in the Himalayas between China and India, it has retained its essentially agrarian and medieval character. Its wondrous history and geography are still the defining aspects of everyday life.
Since Nepal first opened its frontiers to foreign visitors in the fifties, it has been the epicenter of Himalayan adventure activities. Climbing and trekking holidays in Nepal Himalaya has become highly sought after adventure sports throughout the world soon after the advent of tourism culture

My family is from Cusco, Peru. (Your destination in order to visit Machu Pichu). I've lived in the SF Bay Area for fifteen years and I go to Peru at least once a year. This is my third year organising tours to Cusco and Machu Picchu. Because tourism is the main industry in Cusco most of my family and friends have been involved in tourism for many years. This gives me an insider look, and puts me in a great position to get the best values.
Cusco is one of my favorite travel destinations. There is something interesting for every body. Great history, magnificent architectural complexes, wonderful arts and crafts, beautiful music, exotic customs and traditions,unique scenery and wildlife, varied and exciting adventure sports, as well as a fun night life