How difficult is it to...

Dunno your model but you can usually tell by looking. If it's a tight fit between subframe and engine, it will usually mean either raising the engine or dropping the subframe. If it's mounted clear of these might be quite easy. But I'd guess the first is more likely on modern cars. But what is the fault? Most usual is wear on the inner ball joints and the trackrod complete can usually be replaced in situ. A bad leak usually means replacement.

I'd invest in a Haynes if they do one - it's the sort of thing they usually cover.

If it's similar to the last one I did then it's quite high on the bulkhead & fairly easy.