Definitely don't travel via Paris : way too expensive and most trains are sold out weeks in advance. The route via Switzerland is much nicer and cheaper. Would you like to do it in one day ? On which date ? If you let me know, I'll gladly give you advice.

Rome - Milan by Frecciarossa (3h-3h30) costs 13€ per person via ÖBB. It is pretty much unavoidable.

Do not take the EC into Switzerland : 10€ for no time benefits. Instead take the RE train to Lugano.

Seat reservations are optional in Germany but very recommended : 9.80€ for the whole family through DB. Otherwise you won't sit together and may even have to stand.

ICE trains into the Netherlands have mandatory seat reservations this summer : 3€ through ÖBB. Book well in advance.

Other option : night train from Zurich/Basel to Amsterdam -> only one pass day used. About 30€ per couchette. Very popular, most summer dates are sold out. Check on nightjet.com (Basel has more availability).

Which trains exactly do you want to book (route, date, departure time for each train)? There are several routes possible, the ones avoiding France usually a lot cheaper.

The route I'm planning on is through Switzerland (Rome-Milano-Lugano-Basel-Ffurt-Ams). I'll look into DB and OBB sites and I'd like to reserve as much as I can/need.. (would like to avoid sitting on the floor with kids aged 3 and 7 while traveling for 15 hours...that's a bit too much). Planning to do it in one day...some connections are very tight (4 mins in Lugano..) but let's see! 

Just the Trenitalia part is weird, can't seem to book anywhere but on the Interrail app itself. 

Thanks for the advice! 

You can book Roma - Milano on ÖBB : add Interrail as a discount and select one-way tickets.

It'll be a good idea to have 1h margin in Basel to have a break and in case anything goes wrong.

You should be able to go via Cologne and avoid Frankfurt but that depends on schedules (esp. as there are big engineering works in that area this summer).

If you'd like advice, mention your travel date (this is important for the works). I'll gladly help.

So nice! I've seen routes via Köln, will look at it later (traveling 6th July if still possible). 

Yeah definitely possible, although it'll be a long day !

- FR Roma Termini - Milano Centrale 06:25 - 09:24 13€ ÖBB -> loads of available seats

- RE Milano Centrale - Lugano 09:43 - 10:58

- IC2 Lugano - Arth-Goldau 11:02 - 12:11

- IR26 Arth-Goldau - Basel SBB 12:15 - 13:56

Those last 2 connections are guaranteed : it means that if the previous train is delayed, the next one will wait for a few minutes. You won't be the only one making that connection either. Seat reservations are not needed or even possible on those 3 trains. Some advice : people are lazy and mostly board the train in the middle.

I guess the best option is to go via Frankfurt and have a margin there :

- ICE Basel SBB - Frankfurt (Main) Hbf 14:13 - 17:08 3€ per person on ÖBB (or 9.80€ for everyone with a seating map on bahn.com)

- ICE Frankfurt (Main) Hbf - Amsterdam Centraal 17:57 - 21:59 3€ ÖBB

I believe this is the connection you've found too ?

Thanks a lot again!! 

Also the suggestion for the nighttrain...I can still take it, adding some 100 euros, now doubting if it’ll be worth it or we just play tough and do it in one day, argh!

I seem to have trouble with OBB, it gives me zero options to buy seats on Italian trains What am I doing wrong there? I tried with and without discount option. 

Did you choose "One-way tickets” as advised above? The option "Seat reservation only” does not work for these trains.

Thanks a lot again!! 

Also the suggestion for the nighttrain...I can still take it, adding some 100 euros, now doubting if it’ll be worth it or we just play tough and do it in one day, argh!

 

I seem to have trouble with OBB, it gives me zero options to buy seats on Italian trains What am I doing wrong there? I tried with and without discount option. 

 

It says “without discounts” in the passenger details. You need to add Interrail/Eurail as a discount.

Do not use “seat reservations only”. But do like you would book an ordinary ticket, with the discount Interrail/Eurail Global pass.

Ahhhh that’s it!! Sorry to not have followed your careful instructions... Decided to do it in one stretch, let’s see how that works out! 

Then have to work on the way back, but now I know how the system works and that there are still seats available, I’m a bit more relaxed. We may even stop over in Basel or something, since we still have two extra travel days.