Kasol,manikkaran and Tosh, all the three places are near by and u could also cover malana if u are intrested, these could be covered in 4 days, and a over night journey from Delhi takes you there.
The Goa Carnival is from 2nd to 5th March... the main Carnival parade is on 2nd March in Panjim, North Goa. Tourists from all over India flock to Goa during this time of the year to enjoy the Carnival festivities & parties...