You haven't mentioned your itinerary but here is some info on what we have done. Been to Fjords 3 times and love it. Bergen - we did a full day excursion to the Hardanger Fjord which was excellent and well worth doing. On further visits to Bergen we have taken the shuttle bus in to town - lots to see including the fish market and funicular railway.
Stavanger - we took a boat trip and saw the Pulpit rock from below - it was a glorious day and the scenery was fantastic - also waffles, jam and cream - yummy!.
Oslo - did hop on hop off red bus on our own - excellent value for money.
Flam - the railway is a must but would recommend you do it on you own and save a heap of money. We pre purchased our tickets from Stavanger railway station a couple of days earlier and avoided the queues in Flam.
Gerainger - beautiful but not much to do there other than a visitor's centre - my hubby went on an orgainised walk. I took a scenic drive but not much to see as the weather was bad.
Hope that this info helps - have a great trip.
There is no way you will be able to get to the north cape independently as there is no public transport. It is certainly worth going on an excursion even if only to stand on the edge and marvel at what lies over the horizon. Not a lot there, a museum/ shop, an impressive monument and statues but it is the atmosphere and environment you go for. I would not have missed the experience.
If Olden is one of your stops why not visit Briskdalen Glacier. We went as a family and ever our teenage kids said it was worth the walk there. We did it independantly catching the bus from outside the port which took us all the way there and waited until it was time to come back. We had 3 hours there enough time to do the 40 minute walk each way and plenty of time to take in the great scenery. They served lovely hot chocolate in the cafe.