A trip consisting of around 10 to 12 days would be enough for you to enjoy the best of Nepal. During this time, you can visit some of the best cities and their attractions, indulge in activities like treks and camping, explore the local markets and areas. However, if you are looking for a shorter trip then 5 days would suffice for you to be able to visit Kathmandu, a few nearby villages and be able to enjoy activities.