I'm looking at interrailing for a week at the end of August with my two DC (13 and 11 years old). The plan was to get the Eurostar to Paris and spend one day and night there then head down to Nice for a few days before heading back to Paris (and taking in a quick trip to Disney) before heading home. I can get the interrail passes for £360 at the moment but I'm feeling a bit nervous about the whole thing - I can speak a little French but only really what I can remember from my GCSE 20 odd years ago! I'm pretty sure I can reserve my seats on the Eurostar and the train to and from Nice but when it comes to little journeys like Paris to Marne-La-Valle (where Disneyland is) do I just show our passes? Or do we have to go to a ticket desk and show them to get tickets? Are the trains airconditioned? I don't fancy 5 hours on a boiling hot train in August! Any advice and tips would be appreciated! Thanks :)