Here is even better route, thinking outside the box: Namche - Tengboche - Phortse - Thore/Thare - Nha - Gokyo - (Cho La) - Dzongla - Lobuche - Gorak Shep - Dingpoche - Phortse - Namche etc. Reasons: on more day of acclimatisation in Thore/Thare, going to upper kharkas to see snow leopards, rustic quiet lodges at Thore/Thare and Nha looking down at the low Dole - Machermo trail, getting to hike the amazing Pangpoche to Phortse High Scenic trail. Much less trakkers more impressive trails.
Yes, I wondered about it from the other side (Dole) - what would it be like to trek on the phortse-gokyo trail. Looked so isolated and remote. I think this is also the option if one doesn't wish to cross cho la. Namche-Gokyo, come back via Phortse to Tengboche.
