My sister & I will be in Scotland from ~April 4 until April 14,. 2012. I was planning on purchasing the 14 day Discover Passes when we get to Scotland, but I just noticed the Historic Scotland passes. Can someone please explain the difference? My sister & I will be seeing an equal mix of battlefields, castles, museums, parks & gardens (ie. Inverewe Gardens, the Culloden Battlefield, the Inchmahome Priory, etc). Which pass do you recommend? Thanks in advance.