Well, thats prob best put to the people who are going to end up wearing it. i.e the facebook group.
we seem to have most of the details sorted out for the macroscopic side of the route, barring next years timetable changes buggering it all up, but we've got small scale stuff to work out, Lisbon especially, So we're going to be looking for input on a route round Lisbon's trams for a few hours, tram 28 etc and these funiculars, and some of the fine details in the others especially if there's a special tram we can sneak in.
Theres also the booking/reserving for the whole shebang. I got no reply from seat61's TURista. So we need to find someone who knows how and where to book groups of people onto trains in and out of Istanbul with interrail passes.
Norway and sweden need to be done locally, they dont offer the cheap fares to other operators (I think they can get cheap fares off each other) .
The not-the-bernina. i.e this cattle truck, needs to be done with STC,
Renfe probably have to do the iberian trenhotel sleepers,
Eurostar need to do the run at least as far as Amsterdam, and I think we wont have the pass kick in till copenhagen so they will probably be the best option to do it all the way to there, and back from paris.
I think the rest of it can all be reserved at one point of contact. But if that's interrailnet (for the passes) or one of the others i.e. eurostar. stc, renfe or swedish or norwegian railways, I dont know. depends on who knows what they are doing. Now I've got someone with a bit of gumf at swiss travel I'd instinctively plump for them.