I know little about passes.

The German http://www.bahn.de/p… or Swiss http://www.sbb.ch/en… web sites are good for finding routes, even outside of their own countries. When you look up a trip, you will find that there are many options; some trains make few stops, some make many. I would say as a general rule that the trains that make more stops have less fancy equipment and cost less, but take longer, but the differences are not great, and both will get you there.

Generally, the passes and point to point tickets recommended by this website will work for an itinerary submitted and it should be the cheapest option. However, I don’t see why a Britrail pass was recommended since you don’t appear to be doing any rail travel in Britain. Point to point tickets will probably be cheaper than using a Britrail pass for any day trips from London. The same is true in Ireland, where point to point train and bus tickets (the Irish bus system is more extensive than the rail system) for day trips from Dublin will probably be cheaper than adding Ireland as a 4th country and extra days to your railpass.

Your railpass will be your ticket for any train you choose to take in the countries it covers. Often using a railpass is cheaper than buying a ticket for the route, but for short trips it’s sometimes cheaper to buy a ticket than to use a day of the railpass. If you’re traveling in a country that isn’t covered, buy a point to point ticket at the station to cover your travel in that country. Show your railpass to the ticket agent and tell them where you to go. Writing out departure city, arrival city, date (European format — Day/Month/Year) and departure time and/or train numbers will make it easier.

The links in Cleveland’s post will show you times and any connections you need to make. You may want to fly from Paris to Venice, but an overnight train works well on that route, too. You’ll want to fly from Dublin to Amsterdam and to London from Rome. Keep your route flexible in case you find large differences in pricing — it may be cheaper to fly to Paris instead of Amsterdam from Dublin or to London from Venice instead Rome.