You are over 50 it means you have seen and experienced enough with your life. But if havent visited Nepal then its may be the final destination to visit.
Awesome site and view of pure natutal resources like mountain may not be enough for you. Many national parks and wild life reserves offer camping sites so that you could closely experince the nature and its element.
You could easily take in a trail each day and return to the hot bath or restaurant at night to relax. In any of these trips schedule yourself plenty of time to relax each day.
