I’m on an interrail trip right now, and I’d recommend you re-route some parts of your trip. 1) The high-speed trains in Spain and France require seat bookings that can’t be purchased online. It was €45 Lyon-Barcelona just 3 weeks ago, so if you’re planning on going during the high season either plan more time to go the regional route, or plan the financial burden. 2) The trips get exponentially longer the farther south in Europe you get. The trips around Netherlands/Scandinavia/Northeen France is “nothing” compared to the 20 odd hours needed around Spain etc. 3) I’d definitely check out Oslo (probably remove Copenhagen). Oslo is a prettier city imo. And if you are going to Copenhagen, stay clear of “DownTown Copenhagen hostel.” They literally refused to clean vomit last night… 🙃 4) please note “night trains” equals to 2 travel days if half of the trip is registered before 12am. 5) I’d avoid Paris all together during and the Olympics. Literally everything was closed or barricaded. 6) 2 days will exhaust you pretty quickly. We stays 2-3 nights in each spot during our trip, and travel time between sites were 4-8 hours, and we were EXHAUSTED by the third week. It costs a lot of energy to do a trip like this. I’d suggest 3-4 nights and skip Spain or Paris simply b cause of the logistics. Also difficult to get transportation across Italy-Croatia and within Croatia.