In reply to LloydRayner:
Did the 3 Monts a few years ago around 12th September. Left the Cosmiques at about 1am, summitted about 7.30 and descended the Gouter route- the train wasn’t going all the way to the Nid D’Aigle so had to descend to the next station. Arrived back in La Fayet around 3.30pm. Very feasible to do with one night in a hut as long as fitness/acclimatisation and skill set are all good.
edit- make sure you check the condition of the bergschrund on Mont Blanc du Tacul before you go up- last time I was there in September , just pre covid, they were recommending 2 axes for the leader to get across it. It is different every year.
Post edited at 13:49