If you want to use point to point tickets on some parts of your route, check the following websites...
Italy (e-tickets): http://trenitalia.raildude.com
Germany (e-tickets): http://bahn.raildude.com
Sweden: sj.se and Denmark: dsb.dk
Prices depends on date.
Night trains are all listed here: http://www.raildude.com/en/interrail-night-trainRome - Munich
: you can book online via http://bahn.raildude.com
(see information bellow the map)http://www.raildude.com/en/interrail-ni ... 4-lupus/34
If you book early, you can get as well nice special fares without Interrail!Munich - Prague
: there is no night train on this route. If you travel with Interrail, avoid the buses as they require a reservation (EUR 10), use the free trains: http://www.raildude.com/en/interrail-tr ... public/107Berlin - Copenhagen
: also possible by night train via Malmö (EUR 19 in 6-couchette). Not running daily - read here: http://www.raildude.com/en/interrail-ni ... express/58
From Malmö by free Öresund-train (very frequent) to Copenhagen: http://www.raildude.com/en/interrail-tr ... denmark/33
If you like mountains, change your route a little bit and cross the Alps for free from Milan to Switzerland. It's possible to get to Munich from there in the evening (either from Chur or Zurich): http://www.raildude.com/en/interrail-tr ... erland/767October
: you should be fine to make reservations only some days in advance. But it is not possible preview it. Sometimes there are local holidays, weekend (Friday and Sunday nights), ......
That's it for now ... and if you like, support Raildude and buy your ticket here in the Raildude shop. Free shipping to the UK! Thank you,