Nepal’s Western Region

1. Simikot, HumlaYou can fly in from Nepalganj and maybe read --Spy on the roof of the world-- by Sydney Wignall before you go. Permits are 90$ /person /week.
2. Rara Lake4 days walk from Jumla to this the largest lake in Nepal. Getting to Jumla though is either a plane/helicopter trip or a several days long jeep ride on a mountain road that’s still under construction -- and will be for any foreseeable future.3. Upper DolpoFirst of all, see the movie --Himalayan Caravan - L'Enfance d'un chef-- (Eric Valli 1999, Oscar nominated). It's mandatory! Might want to pick up one of his books as well. Having done that, you'll want to go to the Phoksundo Lake, which you can do in 1 week or as part of either the 15 day Dolpa Experience Circuit or the 20 day Dolpa Heritage Trek, all out of Juphal --airport--. Another couple of one-week'ers are the Sundaha Nature Trek and the Sahartara Tour. Expensive permit are required, as in Upper Mustang it's $70 /person /day with minimum 10 days. No lodges. Annual number of visitors are in the low hundreds.
4. Lower DolpoPermits are 10$ /person /week. You might have to fly in from Nepalganj. Don't expect lodges here, so bring your own camping gear.
5. Upper Mustang10 days. Home to the ancient kingdom of Lo, still in existence - sort of. Hefty permit required north of Kagbeni, $70 /person /day with minimum 10 days.
Annapurna Region
6. Dhaulagiri 20-30 days to complete the circle around this 8000+'er. Bring good boots and sleeping bag!
7. Annapurna Circuit2-3 weeks minimum. This is where everyone goes. Except me. In the high season it gets rather crowded and is more appropriately named the Annapurna Circus. Lodges and tea-houses are everywhere. The Thorung La high pass (5400 m) usually closes down in the end of November. If you bring your own camping gear, there's also good possibilities of doing side trips off the beaten track. ACAP entry fees stand at 2000 rupees.
8. Jomsom & MuktinathYou can fly into or out of Jomsom, a days walk from Muktinath, and hike to or from Pokhara in about 1 week. Muktinath is an important pilgrimage site nestled at 3800 m. It's on the Annapurna Circuit.
9. Annapurna Sanctuary & ABC10-14 days, 2000 rupee ticket. Another popular option, since it’s shorter and a little less demanding than doing the full Annapurna Circuit.
10. Ghorepani, Poon Hill5 days out of Pokhara, it reaches 3200 meters and is accessible all year round. Famous for it's views of Annapurna, Dhaulagiri and rhododendrons in the spring.
11. Panchase Peak & GhandrukAnother holy mountain, this one a couple of days walk west of Pokhara. Ghandruk is 3 days further and it's home to the Annapurna Conservation Project and a whole lot of Gurung people.
12. The Royal Trek4 days out of Pokhara. With altitude no higher that 2000 meters it's open all year round.
13. Siklish, Begnas Lake, Lamjung1 week return trip from Pokhara, 10-12 days through Lamjung to Besisahar. Lodges should be available, 2000 rupee ACAP permit required.
14. Manaslu3 weeks, circle around this 8000+ m twin peak that can be seen all the way from Kathmandu. Pass over Larkya La at 5110 m. There's no lodges and the mandatory permit stands at almost $100 /person /week.
Central Nepal
15. Trishuli - GorkhaThe easy way: 4 days along the route that Prithvi Narayan Shah took in 1768. Apparently has village lodges and stays under 2000 m all the way.The hard way: 2-3 weeks on remote, off the beaten track. Passes over Sing La (3570 m) and by the Jogeshwar kund (4500 m). Camping gear required.
16. Ganesh HimalNo lodges, rough and remote. But wow, wouldn't I like to go there! The highest peak is well over 7000 meters, and it’s prominent view from Kathmandu makes it all worthwhile if you like to brag about your adventures when you get back to civilization!
17. Tamang Heritage Trail8 days, lodges still under construction.
18. Langtang & Gosaikunda / Panch Pokhari1-2 weeks minimum. Third most visited in Nepal, after Annapurna and Everest. Fairly easy, not too crowded, especially the Gosaikunda lake area (4400 m) which is arguably the most scenic. Langtang Valley has lodges every hour or so all the way to Kyanjing Gompa (3900 m), the Gosaikunda trail has fewer, but still enough for short days. Gosaikunda features the annual Janai Purniam festival and from there, you can walk back to Kathmandu in 2-4 days. Entry fee 1000 rupees.
19. Helambu½-1 week, more jungle than mountains but still a rough trail. Tea-houses available if you don't get lost like that Australian guy. Distant, but awesome mountain views before you get too close to the mountain bases. --Walking distance-- from Kathmandu, circuit from Sundarijal to Nagarkot (4 days).
20. Namobudda1 day, one of the few quickies you can do when the noise and pollution of Kathmandu starts to get on your nerves. Take the bus to Dhulikel and start walking.
21. Rolwaling & Gauri Shankar2 weeks or so. Get up close and personal with Gauri Shankar (7130 m) and it’s glacial lakes. Good view of Everest etc. Unspoiled landscape, permission still required but check with Nepal’s Tourism Board when you get here. There’s rumors that they’re making this one permission free.
22. Chitwan Chepang Hills7 days in the Middle Hills. No Himalayas and no higher than 2000 meters so it could be a good winter trekking possibility. Good view of the (distant) Annapurna, Dhaulagiri, Ganesh Himal, Gauri Shankar, Gurja Himal and Manaslu, but the main attraction is the nomadic Chepang people who live as hunters and gatherers. There's also a fort, a waterfall and some caves along the route together with 400 bird species. Start in Hugdi on Prithvi Hwy, end Shaktikor in Chitwan. Homestays are on the route.