My friend did this itinerary for me: "Saturday morning, after breakfast, we can walk from my house down to the ferry (15 min). Then take the ferry over to the Viking ship museum, stay there for some time
before we take the ferry back. Then we can take the tram/or walk to the Viegeland Park. We can bring with us lunch and have a picknick after a round tour among the sculptures. (The park is only 5 min walk from my place). After lunch we can take the subway to Holmenkollen, In the evening we have dinner in the city. Later, I'll show you some of Oslo's nightlife. Sunday morning we can visit the old city and do whatever you want to do till your flight time."

I will stay in my friends home. Do you think the transportation strikes will effect this itinerary?

And one more question: If my flight to Oslo will have delay, I'll miss the last train to city. Then I have to take a taxi, right? Any other options?