From Tredjetoppen ski directly down towards the south on the easternmost of the "5 fingers". This is a fun 30 - 35 degree descent on its own. At 1000 metres take a hard left and wrap around the ridge and then ski down into a drainage via a short but steep (40 degree+) drop.
Put your skins back on and hike to the col between Tredjetoppen and Moskočohkka. On the col, take a right and follow the ridge. Stay on the right hand-slopes of the ridge clear of the left hand edge - there are cornices and a steep drop. About 50 metres below the summit you can either stop to begin the ski descent or take skis off and hike to the summit on an exposed ridge - on this last section there is serious fall hazard!
The descent starts 50-60 metres below the summit on a flat and broad section of the ridge. You cannot see the run from there due to a convex roll...be careful on the first meters when looking for the slope. A few metres down it becomes visible. The slope below is between 35 and 40 degrees and offers great turns. Beware - beneath you is a cliff and before the drop you must ski right, for a few more turns in the fall-line. Traverse hard right to get back to the drainage where you put your skins on. You can now do another run, hike back to the resort and ski Tredjetoppen north side, or head to the col and ski the equally exposed and exciting ramp down to Fornesvatnet. This way you can get corn snow on Moskočohkka and then powder on the north faces!