Part of the beauty of Nepal is that there are amazing day hiking opportunities within easy access of all major tourist cities.
You can choose from an amazing sunrise tour for a nearby hill station such as Nagarkot in the Kathmandu Valley to witness the view of Mt Everest or Sarankot overlooking Pokhara to soak in the Annapurna Ranges, then follow this up with a hike through the local countryside.
Alternatively you can sleep in and then take a guided hike through the nearby hill of the Kathmandu Valley or around Pokhara and be home in time for dinner.