There are several national parks in southern and western Nepal. Chitwan is the most famous. Bardia is much harder to get to but may be attractive since far fewer tourists take advantage of it and it apparently has much better wildlife populations. Lumbini is the official birthplace of Buddha.
^ Chitwan National Park, Lumbini and Bardia National Park
After some R&R in Pokhara, a visit to Chitwan and/or Bardia may be nice. A return to Kathmandu would be needed if an exit to Tibet from Nepal is planned.
^ Chitwan National Park
A 4-6 hour bus trip from Pokhara – Greenline US$17-20 to Sauhara is probably why Chitwan is popular.
Sounds like accommodation at Chitwan Gaida Lodge would be a good choice. Refer to The Longest Way Home guides for more information.
Ox cart tours, private elephant trek (1.5hours) & 3 day jeep jungle package.
The direct return is 5 hour by bus to Kathmandu.
^ Bardia National Park
Alternatively, a trip to Bardia National Park if the 12 hour bus trip is tempting. This may include a tourist bus from Pokhara to Bhairhawa (7-8 hours) and change to Ambassa (7 hours). 2 hours longer but one half is on a better bus and you get a break halfway. You get off at the gate at Ambassa and hopefully get picked up by your accommodation. It’s another 13km to the accommodation areas near Bardia. The Forest Hideaway Hotel and Cottages sounds like a good bet for a stay.
The official birthplace of Buddha. It’s not far (30 minutes) from Bhairahawa, but Bhairahawa is at least 7-8 hours from Pokhara. It could be a good way to break the journey from Pokhara to Bardia which would be a 12-14 hour bus in one hit via Butwal.
Lumbini is nearly 8sq km of gardens and temples. Not sure if that is too much temple for me.