I don't know. Is 31 years? .
We were at Cragside on Sunday too . I felt that the price for the gardens alone was a bit steep so if you think that your dc are old enough to appreciate the house (which is lovely) then I would pay for that.
Alnwick Castle and Gardens are a must and could easily be a whole day with a walk around the town.
Bamburgh is beautiful.
I love Warkworth, my favourite castley village. Lovely walk along the river and a nice beach too. Great icecreams at Morwick Dairy just along the road from there.
Other cool castles at Etal, Ford and Norham. Ford holds many happy memories of school residential trips for me; GCSE History and Geography and then again for A level Biology .
Alnmouth is lovely, there were a couple of Spring Walks published in the Times on Sat, one was around Alnmouth I think and the other around Hadrian's wall.
Morpeth is a pretty market town and Whitehouse farm is good.
There is a colliery musuem at Woodhorn Village which I've not visited but is meant to be v.good.
I would do a day in Newcastle to see the Millenium Bridge and walk around the Quayside. There is a nice cafe at the Baltic and the Pitcher and Piano on the quayside is ina good spot for a lunch too (kids are v. welcome) and Piccolinos is also around here and yummy. You could combine it with a trip to Segendum ?sp, a Roman site in Wallsend.
Tynemouth is great too, lovely beach and the Priory.
I'd also definitely recommend a trip to Durham, fab as you come in on the train.
If you like Indian food I'd also recommend the Valley in Corbridge or it's sister restuarant in Hexham.