"This is a very fun journey."
Translation:זה מסע מאוד כיף.
To me, a מסע is long and requires effort. What distinguishes a טיול is that its purpose is fun. So they're not mutually exclusive. So IMO a מסע is close in meaning to journey, and טיול to trip, but a business trip is never a טיול, and a trip abroad would only be a מסע if it's long and hard and you intend to walk lot.