Before I answer further, I just want to emphasize that since you're planning to travel in August 2025, per your other posts, you really need to make a plan and start making reservations. Hotels, trains, etc,... are getting booked by other travelers as I type this.
The NIN sights can all be done in 1 day. In fact, that's how most tourist do it. Per your other post, you are struggling to find acceptable accommodations in your budget in Flåm. Just make it a long enjoyable day.
My guess is that you won't find many posters here who follow Rick's itineraries exactly. While Rick Steves and his guidebooks are an excellent resource, sometimes following his suggested itineraries just don't make sense
For a 2 week trip, IMO 2 countries is perfect. I would plan Norway and Denmark since I believe you have booked air roundtrip to Copenhagen. If your family is hikers, Rick's itinerary isn't giving you time to enjoy the many possibilities in Norway. For Vikings, NIN and fjords, spend the bulk of your time in Norway.
No matter what you decide, you'll have a fantastic trip. Good luck.