There are several camp-sites in Lebanon - okay, but no need to hyphenate
"I will spend my holiday with my friends at a golden campsite" - I assume that 'golden' here is the proper name of a campsite, as in a chain of campsites owned by the Golden company? If so, it should have a capital letter - Golden. If golden here has some other intended meaning,, please clarify
Lebanese people prefer to have OR spend their vacation at a campsite". "Take" would be more usual than have. Take a vacation, spend a vacation at a particular location.
I told me neighbour to bring his children because they will have a lot of fun at our campsite" - this is okay
What do people usually do at a campsite" - this is fine too