Jiri to EBC trek
This is old route which all the earlier expeditions took, before any airports. It has two parts - from Jiri To Lukla and from Lukla to EBC. The first part is much more difficult that the second, but gives a proper acclimatization and endurance training. It is definitely not for pot-bellies due to multiple 800 up to 1000m steep ascending (think of 3-4 hours of steps non-stop).
It is a unique opportunity to visit beautiful Sherpa villages, not ruined by grotesque greed and sticking inequality (the way of Lukla or Namche Bazaar are).
I have completed full Jiri-EBC-Jiri trek in 13 days with casual clothing (two years in a row) and I think this is a moderate Sherpa's level.My pictures from