There is a discount for the Eurostar for passholders. At one time the answer would be buy a pass; unfortunately hight speed trains have limited seats allotted for EP, and supplements kick in. A
full EP would be very expensive and cover countries you are not going to see. There are 5 country
select passes which could cover all of your continental spots (except Finland). [I don't think Germany charges a supplement for IC trains.]
How were you planning on getting to Finland? The most direct route is by boat, but this does not cover private cabins(extra fee), you get dorm or chair spaces. I don't think the all rail route still exits, and in any event would take days to get from Stock. to Hel.
You have little choice but to use RailEuope for buying passes (they have the monoply
). But if you wanted to plan out a point to point ticket itn., RailEurope will hit you with high fees and supplements.
Go to
www.raileurope.com to see EP pricing
www.bahn.de will give you schedules.
Cooks publishes a European Timetable, which is a necessity to have for extended rail journeys. If you have lead time to buy one, it can give you clues about optimal routing.