I know exactly what you mean about multi-purpose holidays! I often have to weave a deft bit of to fit in the Prehistory on my family holidays. It is a great wee trip out to Inchcolm, I used to live by the Forth and visited the island and Abbety many times. If you are driving through Fife, before or after taking the boat at South Queensferry, you could do a lot worse than dropping by Falkland Palace.

http://www.nts.org.uk/Property/Falkland-Palace-Garden/#

Fascinating bit of renaissance survival in Scotland. And in the renaissance chapel, the icon of the Virgin made from corned beef tins by the Polish Army in exile during WWII, is worth a visit alone.

http://flic.kr/p/9C4iRZ

Falkland is of course the ancestral home of The Man In Black, Mr Johnny Cash. You might be lucky as his daughter Rosanne Cash likes to drop by!

http://www.rosannecash.com/gfx/monthly/falkland_palace.jpg

And of course. thanks to Dan Brown, entry fees have gone up somewhat (ahem...), but Rossyin Chapel is a medieval marvel and an incredible scottish survivor. Either en-route North or driving back South. If you haven't seen it, take some spare socks, because the place will blow the ones you are wearing clean off.

http://www.rosslynchapel.org.uk/