I'm rather disconnected from the main musical society where I live (in the middle of nowhwere), so does anybody have any subscriptions to good horn/music magazines that they could suggest or know of any?

I would recommend joining the International Horn Society.
They have the Horn Call that comes out quarterly.
They might also have other sources that may come out monthly.

Also Dr. John Ericson at Arizona State University has a blog site that he regualrly posts on. You could spend some time going through his site. If you thnk about buying his books think twice. It's not that they are not good but they seem incomplete. All the information in the books is in the website. And ti seems the website entries make more sense. The books seems to have been edited by someone other than himself and there are just a lot of incomplete thoughts.