You can go To Goa;I visited the goa in Dec 2015.The beaches are decorated like a bride.At that time;the famous Sunburn festival also get organized there.You can go to cruise for the parties.And away from the beaches is peaceful,clean,less crowded area i.e. South Goa.Hire A scooty and wander all tha goa with the help of google maps.In other options;you can go to Jaiselmar and Rann of Kutch. Or if u want to see the snowfall go to Shimla or Manali.
Holaji provides quality tour and travel packages of whole World. It offers national as well as international tour packges like india travel packages,
https://holaji.com/
December end, definitely Goa if you are party kinda person. kerala weather would be pleasant too to visit. ooty kodaikanal can be worthy too coorg is al sdo an option up north you can visit rajasthan jaiselmer