"This is a very fun journey."
Translation:זה מסע מאוד כיף.
Either or both. :-) In real life, it just magnifies the emphasis on whatever the person is trying to say.
From your question, I don't know if you're a native English speaker. Fun can be an adjective or a noun in English. Funny is only an adjective, but refers to things that are ridiculous or silly, like a clown or a comedy movie. In Hebrew, that would be מצחיק.
What you wrote means "enjoyable", which isn't (in English or Hebrew) the same as fun.