Going to Norway late October is a gamble any which way. We're talking 62 degrees north up here; chances are it will be rough. It could be rain. It could be storm. It could be fog. It could be all three at the same time or alternating throughout the day.
Tell you this though; if the weather is clear and perhaps even with a bit of sun in the last half of October, then the bare thought of getting into the mountains of my native Western Norway, with autumn colours and air so clear and crisp you could cut it in bricks, puts shivers down my spine and perhaps even a tad of moisture in the corner of my eye.
So, what you need to ask yourself, is:
Do you feel lucky? Well, do you?
(BTW, your itinerary seems entirely doable. Inner Sognefjord from Bergen is also quite doable as a daytrip by car, even considering that daylight shortens fast in October. But try to get into the terrain, either with local guidance at Sognefjorden or at the end of the Fløyfjellet funicular).