It's all about the experience for me, Marcus.
During the trip from Vladivostok to Moskou, I will make 2 or 3 stopovers. Lake Baikal is certain, Jekaterinaburg big change, and 1 or 2 others. Not sure yet where exactly.
And from Moskou i'll be flying to st Petersburg and from there back home.

this is the trip approx:

Amsterdam - beijing flying (obviously :P)
beijing few days incl. chinese wall
then fly to seoul
seoul 1-2 days
fly to vladivostok
vladivostok 3-4 days
train to Irkoetsk/lake baikal (maybe a one day stop over somewhere, not sure yet)
Irkoetsk/lake baikal 3-4 days
-----> maybe, depending on time and the level of 'worth your while' a little detour to mongolia
Irkoetsk to Jekaterinaburg (maybe a one day stop over somewhere, not sure yet)
jekaterinaburg 2-3 days
Jekaterinaburg to moskou (maybe a one day stop over somewhere, not sure yet)
moskou 2-3 days
fly from moskou to st petersburg
st petersburg 3-4 days
fly back home

It's all about the experience, meeting de local people, getting a little taste of their lives, getting a little taste of russia. You don't get to know russia and their people on an flight :P
And by train - with all my stops - is much cheaper. The whole trip will be expensive enough as it is