I planned to return to DoTA 2 after a-half year hiatus. I might planned to use CK, PA or Viper that I can play well.
Since the last update, is CK viable to use in Offlane? Is any thing required to prevent ganking on CK?
No, the hero has no escape mechanism which is key on offlaners. He cannot fight a trilane nor transition well with no farm.
Play CK as a roaming 4 and abuse his strong stun if you must. Otherwise an aggro duo/tri is also good.
Usually offlane heroes have an escape mechanism, CK doesn't have that. Offlane heroes benefit from getting experience, while gold is a bonus. CK, on the other hand, requires items to function well, hence gold is more important than experience.