Is the Japan Alps route better for a first trip or second trip?
The Alps can work on a first trip, but only if you cut something else. Otherwise they are better as the spine of a slower second Japan trip.
Answer
Central Japan’s mountain routes are rewarding because they change the texture of the trip: smaller cities, old towns, castle stops, highland air, buses through valleys and a slower sense of movement. That is also why they do not fit every first itinerary. If you already have Tokyo, Kyoto, Osaka, Fuji and Hiroshima, adding the Alps can push the trip from rich to restless. The region shines when it becomes a chapter, not a bridge. First-timers should include it only when mountain towns and regional depth matter more than completing the classic list. For many travellers, it is a better second-trip foundation than a rushed add-on.