Looking at your profile, you seem to be somewhere in the region of Whitley Bay. Is the possible smallholding near there? As well as elevation, latitude plays a part and local climate is all. So the first thing to do is to find out more about that. Just as at sea level, a frost pocket or lack of one is significant. Wind direction and protection will be very significant - if you are in the lea of woodland for example, life will be much easier than if you are fully exposed.
If the area you are looking at is prone to heavy snow and is along an unpaved track, with just you at the end, you will be snowed in each winter, or need your own heavy equipment to keep the track clear. If on the other hand you are right beside a school bus route or a milk collection route then the road will probably be cleared for you.
Length of growing season is important, so you need to know the dates of the first and last expected frosts of the year for that specific location.
Soil at elevation and in areas of high rainfall can be awful - acid and thin - to assess this see what native plants and what crops grow in the area and check their preferred growing conditions. We were very lucky - our smallholding is at 1000' in southern Scotland, which you would expect to be barren moorland good only for forestry. However, we are also on a volcanic ridge so the soil over most of our holding is wonderful volcanic stuff, not very deep but perfectly formed
We have no wind protection though so we had to grow our own, in the form of hedging and patches of coppice. Trees take a long time to grow so initially we put up 2m high windbreak netting to give our enterprise a start. Now the shelter we have grown is making an enormous difference to our new micro climate.
Ultimately, whether your proposed new holding will suit you will depend on what you want to do with it. If you just want to keep sheep then you will find a breed naturally adapted for any situation. If on the other hand you want to grow exotic salads for the restaurant trade you would be better off at sea level. We had certain plans in mind when we bought our smallholding 17 years ago, but had to adapt our plans almost immediately to accommodate circumstances - I think this flexibility is very important in making your place a success.