Norway by rail and ridgeline: Dovrefjell, Trollheimen & Trondheim

You don't need a hire car. The spine is the Dovre Line (Oslo–Dombås–Oppdal–Trondheim), your own boots between trailheads and DNT huts, a guided musk ox safari, and short local transfers — bus route 580 or a taxi from Oppdal to the Gjevilvatnet trailhead, a pre-booked taxi from Kongsvoll to the Reinheim trailhead. The one honest exception: if you want to freelance around Trollheimen's several trailheads on your own schedule rather than wait for the summer bus, a one-day rental from Oppdal (~800–1,000 NOK) buys real flexibility. Skip it if you're happy hiking the same lake in and out.

SAS and Norwegian both fly nonstop Copenhagen–Oslo, ~1h10m, roughly 18 flights a day between them — easy to fit an early departure. Coming home, SAS is currently the only nonstop operator on Trondheim–Copenhagen, ~1h35m, 3x daily. Book this as an open-jaw (into Oslo, home from Trondheim/Værnes) rather than a return — it saves the backtrack to Oslo at the end and matches the trip's one-way rail spine north. Budget ~€700 for two with bags in mid-summer.

The Dovre Line (Dovrebanen), run by SJ Norge (branded SJ Nord) with Vy handling regional legs, covers Oslo S–Trondheim's 548km in roughly 6h30–7h, climbing over the Dovre plateau via Lillehammer, Dombås (659m), Hjerkinn, Kongsvoll, and Oppdal before dropping to Trondheim. You'll ride it in stages: Oslo–Dombås (~4h20), a short hop on to Kongsvoll, and later Oppdal–Trondheim (~1h50–2h). Book on sj.no or vy.no; reserve seats in summer, it does sell out.

The Norwegian Trekking Association (DNT) membership costs ~725 NOK (~€63) per adult per year and is genuinely required, not just a discount: most self-service and no-service cabins (including Reinheim) are locked with a standard DNT key, and at least one person in your party must be a member to buy or borrow one (100 NOK deposit, refundable). Self-service cabins run first-come-first-served — no booking needed, you pay via the honesty-box or DNT's app. Staffed cabins like Gjevilvasshytta take bookings via dnt.no or ut.no — book ahead for July/August.

Moskussafari and Oppdal Safari both run guided musk ox tours from Kongsvoll, June–September, ~6h on foot covering 7–15km depending on where the herd is that day (guides track them daily; ~99% sighting rate). Oppdal Safari also offers a horseback version. Expect ~580–650 NOK per person. A free self-guided alternative exists too — the waymarked Musk Ox Trail from Kongsvoll or Grønbakken (4.5–15km loops) — but you trade the guide's local knowledge and safety buffer (musk ox charge; keep 200m+ distance) for a lower price.

For Gjevilvatnet/Gjevilvasshytta: DNT-coordinated bus route 580 runs from Oppdal station to the lake, timed with the Oslo train, roughly 1 July–31 August; outside that window or off-schedule, a taxi (Trønder Taxi, app-bookable) runs ~500 NOK. For Reinheim, arrange a taxi transfer from Kongsvoll to the Stroplsjødalen road-end in advance — there's no scheduled bus this far into Dovrefjell.