Okay, so I've done some research and run some of the places you all suggested past my husband and kids, and these are some of the ones we're thinking off. Wondering if you could render opinions on any you're familiar with:
Treasure Trail through Lacock
Blaise Castle House Museum
Jorvic Viking Center
Beamish Open Air Museum
Ironbridge Gorge - Blist Hills Historic Town
I'm still looking into what we might like to do in Cornwall, as well, but I found a great website that I've been going through to get ideas.
I live in York and can recommend many things! The Jorvic Viking Centre is definitely a place to visit, especially as you have children. The Vikings are all lovely! Jorvic also own 'Dig' (http://digyork.com
) which is just around the corner and the kids can get some hands on experience with archaeology. There are also guided tours by archaeologists. You can buy a family pass that gets you into both of these
You also have to visit York Minster; it is on of the largest Gothic cathedral in Europe and still blows my mine, even though I get to see it on a weekly basis.
If you are here for more than one day you should also try to 'walk the walls', which surround the entire city. They are about 3.5 km, totally free and you will see many of the best sights in York. There are also small plaques at each bar (gate) that are raised, so that children (and adults; I've done it!) can use paper to create rubbings of an entire map of York from it
There are also small museums at the bars but these cost a little for entry.
Ah, all of this has reminded me why I moved here! I think I'll go and watch the sunset from the walls in a little bit
Also, I spend a bit of time in Alnwick. The town is lovely and the castle is a fantastic day out. The gardens are also magnificent and well worth the money. If you are treating yourself whilst on holiday can I recommend somewhere to eat in Alnwick? The Treehouse (http://www.alnwickgarden.com/explore/whats-here/the-treehouse/restaurant
). It is a little pricey but it is magical. You eat in a restaurant in the trees, accessed by a little bridge, surrounded by fairy lights eating some of the best locally produced and caught food I have ever eaten. So magical that my entire family are travelling up to it next September for my father's 60th (and 3 hours is a big deal to my family!)
If you are visiting both look up Henry 'Hotspur' Percy. He was born at Alnwick Castle in 1364, had a very interesting life, and died in 1403. His head was stuck on a spike at Micklegate Bar (you will find it on the walls if you walk them) and the rest of him buried in the Minster here in York. Wonderful history around here
Sorry for rambling! I get all enthusiastic about this little part of the world!