You want them all in one short go: The mountains, the Atlantic Road, Trollstigen and Geiranger. By following this route, you can do it in one weekend. But be prepared for a couple of long hauls.
Day 1: Oslo – Folldal. Typically the leg of an early Friday afternoon. It takes you as a matter of transport along the E6 up to just north of Ringebu. From here, Road 27 – a national tourist road – takes you over the Venabygdsfjellet and let you gasp in awe over the magnificent Rondane mountain range. The day ends in Folldal, where I have tended to book a night at Løkken fjellgård. Book ahead. Bring your own supper, though. The cabins are fully equipped with utensils.
Day 2: Folldal – Valldal. (NOTE: Trollstigen is closed during winter.
This map therefore doesn’t route you along road 63 from Åndalsnes to Valldal as it was routed in February – but you will clearly see where the road goes anyway.) You have the full day at your disposal, so off from Folldal the route takes you down Sunndalen valley towards Kristiansund. Here you will go through an underwater tunnel which takes you to the Averøya island. The Atlantic Road will take you from Averøya to the mainland on the other side. Make sure you take a break at a suitable place on the Atlantic Road. From here, the route takes you to a short ferry crossing Sølsnes – Åfarnes. You continue and will do the Trollstigen. Be prepared for slow traffic up the road, though. Well on top,
stop at the tourist kiosk and buy a sticker. Push onwards to Valldal, where you find youself a camp site for the night. There are plenty along the road 63 Trollstigen – Valldal, but as it is pretty much traffic there in summer you might want to book ahead if you want a cabin. Here are a few options.
Day 3: Valldal – Geiranger – Oslo. Leg 1 -> continue on 63 -> Leg 2 -> continue on 51 -> Leg 3 Be prepared to get awestruck. The day starts with a short ferry trip Eidsdal – Linge. (There is also a tourist ferry Valldal – Geiranger, takes ca 1 hour and costs more). Continue towards Geiranger on Road 63. See the sights! Continue on 63 where it meets Road 15 (not routed on this map due to being winter closed, but you see it clearly). Just before Vågåmo, turn on to Road 51, which takes you over the Valdresflye mountain road. (It is also winter closed so doesn’t get routed in Google at the time of writing this, but you see it.) Push onwards towards Oslo and you’ve done a pretty long, but satisfying weekend.