Traveling with my grandson in mid-July. Advise train transportation, interesting sights, hotels suggestions,etc...
Fly from Copenhagen to Amsterdam, train between the rest.
1...we want to do Norway in Nutshell on July 7 and 8. what is the best way and can this be booked from NY ? How?? Are two days enough to see fjords, etc...?
2...What links should we use to book Trains from Oslo to Stockhom, then Stockhom to Guthenbrg, then Guthenberg to Copenhagen ??
Long-distance trains within Sweden, and between Sweden and Oslo and Copenhagen, are operated by SJ, whose site is here: https://www.sj.se/en/home.html#/
Even on the English version of the site, Copenhagen central station is listed as Köbenhavn H. The other cities are all close enough to what you'd expect.
You can save a lot of money on SJ tickets by booking them in advance. For a trip in mid-July (assuming you mean this year and not next year), many of the cheapest fares are already sold out, so buy your tickets as soon as you can.
When I priced a sample journey from Oslo to Stockholm, it gave me a message that there's track work south of Stockholm this summer, and you'll have to change to a commuter train for part of your trip. That shouldn't be a big deal, but it's an extra step to keep in mind especially if you have luggage.
For the trip from Gothenburg to Copenhagen, in addition to the high-speed SJ trains, there's a slightly slower commuter-type train that runs once an hour. There's no discount for advance purchase on the slower trains: You can buy your ticket right before you travel and pay the same fare (484 kr). That can be worthwhile if you aren't sure at what time you want to travel. But advance-purchase SJ tickets are considerably cheaper (as little as 235 kr, maybe less, depending on the day), if you're able to commit to a travel time in advance.
For Norway in a Nutshell, do you have Rick's Scandinavia book? He has all the details you need, far more than anyone can put in a post here. These include booking options, how to do it in a day, and how you can break it up if you have more than one day.
The book won't just help with the NiaN trip. It also has lots of money-saving tips - very useful in this very expensive region.
Expect the Oslo/Stockholm trains to sell out one week in advance. Price will quadruple between first offering and last sales, $25-50 initial offering. Grandson about 15% off. Starting June 25 Oslo to Stockholm trains stop at South (Södre) Station which is just short of Central, but it might be near your lodging.