Hi, Nishant!
Overnight camping at the hilltop is now banned by local authorities and you won't find any accommodation up there, but you can still trek to Triund hill and return before it gets dark.
No it isn't I guess as the government has banned camping due to too much trash and garbage at triund caused by it. Due to this the entry to the trek is also closed after 11 am(approx.) everyday so that you can make the hike and be back same day