1. Let your child choose the destination.
And never tell them their reason for wanting to go to that specific place is ‘not good enough’. It can be as simple as they happen to be into bears. Or trains. Or a certain television show that was filmed there. Or they want to go because some kid on their soccer team went there once with his uncle.
If a kid thinks something is his idea, to him the idea must be pretty cool. If the kid thinks the parent came up with the entire travel plan, it’s already questionable in their eyes.