I was there in February, the weather was bad then, heavy snowfall. it's much better now. Rather this is the right time to visit Triund, Mcleodganj, Dharamshala.
Yes the treck is open.
If you plan solo, no harm in checking with India hikes. I accidentally bumped onto their group on a similar treck Nagtibba.. Had fun.. https://indiahikes.com/triund-trek