Another smallholding at 1000' here, in the south of Scotland.
Every place varies, so look at the individual farm, and try to see it in winter as well as summer.
For fly strike it depends absolutely on how sheltered you are (hedges and trees) and how close your neighbours are with animals. When we first came here we had no strike for years, but our newly planted hedges were tiny, and we had plenty of arctic blasts. Then our neighbour put his ill-cared-for sheep next to our fences, and suddenly we had to start using Crovect. Now that our hedges have grown to their full size, we have a different micro climate, so there is always the possibility we'll be struck.
Hedges take longer to grow here than down in the soft south. Where I come from in Norfolk you might expect to have a newly planted hedge ready to lay at 7 years - here it's several years longer than that.
For veg, as others have said, expect to need a polytunnel. I also start many veg off in individual pots in the tunnel, then plant outdoors in late May/early June when the frosts should be over. I tend not to sow things like broad beans in the autumn, as they don't usually survive. Outdoors I can grow potatoes, onions, peas, broad beans, beetroot, leeks, parsnip, broccoli, carrots and tough things like that, but runner beans, all squashes, cucs, sweet corn, lettuce and more need to be under cover, as much for shelter from the wind as from the cold. So, get a much bigger tunnel than you think you'll need, as there will be much more in it.
For fruit trees, some varieties will survive at 1000', although it does seem to be the limit. There are several hardy varieties bred specially for areas with late frosts, so the blossom survives. We have one really good full grown tree, but I can't remember the variety, which produces heavy crops of cookers. Many varieties succumb to canker. This year we have sourced 4 new trees specially bred for our situation, and I have high hope for them: Ellison's Orange, Fiesta, Laxton'e Superb and Worcester Pearmain. I'll know in a few years time if they're any good

Other fruit we grow without problem includes Golden gage plum, Merryweather damson, brambles, rasps, strawbs, gooseberries, black currants, rhubarb (needs shelter or it get flattened in the equinoctal gales)
Oh and get double glazing