If either of you need to work, it'd involve a lot of opening and closing gates in high winds and torrential rain (both together). They always have snow, every winter. If you run out of milk, it's a long drive to pick some up. It will be more expensive to heat than you can imagine - you will probably have the central heating on all year. There is unlikely to be mobile phone coverage.
You could try planting a little forest, but you will find, even if you protect the saplings from rabbits, voles, sheep and deer, that growth will be exceedingly slow - the landscape is treeless for a reason. Living off the land won't be easy - the growing season is much shorter, and you are high enough up that you'll be restricted as to what you can grow.
A few miles away from you is Alston, which hit the news a couple of years back as all the men were advertising for women - any women - to come and marry them because all the local women had got out at the first opportunity.
On the other hand, just down the road is Nenthead, which is heaven for aficionados of mining archaeology - masses of underground exploration to do. And caving further down Weardale.
But if you want the flavour of living remotely in an old northern farmhouse, try
www.landmarktrust.org.uk/search-and-book/properties/cowside-5807