1. Welsh Highland Railway. Good that you are looking at something for 2012 as by then the railway will be fully established along the full length.
2. Hartz there are many cruises into the Baltic. Look there.
Biggest issue with cruises is that you become a "day tripper" to all these places and a day at either or both is just not enough. Possible of course from Holyhead but the Hartz, doubtfull.
You might consider though a cruise through the southern ocean with a stop in Ushuaia where a Garratt will haul you into the Park.
TH