After lots more discussion we've cut our route down to 10 destinations, allowing 3 nights at each, although some train journeys are long inbetween. Our new planned route is.
Milan
Trieste
Ljubljana
Split
Budapest
Kosice
Krakow
Prague
Munich
Innsbruck
Paris
Flight into Milan, we planned 3 nights everywhere except Milan and Paris, 2 nights in Milan and One night in Paris (ha) where we've planned to get the Eurostar home.
A few more questions for those that have done this before.
We're under the impression you can buy your Interrail ticket about 3 months in advance (from looking on the website thye let you buy if you've planned to go up til March) Once you've got your ticket are you free to use it whenever you want in a timescale and your 30 days start from your first journey?
What are night trains like? How much are the couchettes, we've got some long journeys so looks like we might have to take quite a few night trains.
Also, looks like reservation fees could make it quite expensive, some places like 5 euros to reserve your seat, how many lines is this actually on? Or is it only on select ones like high speed
cheers