You said you live rurally - in that case, perhaps you should build/buy a small quality (read as: won't get wet) shed, have your systems there and run some outdoor-rated CAT5e from it to your house. That should allow you to use KVM extenders, serial, etc. Remember the inverse-square law for RF. RF usually is attentuated greatly by opaque things, though just plants etc. will also attentuate. If you can place it behind a hill that would be good.
Also, apply for the JREF Million Dollar Challenge. If you succeed, you should have a lot more options on reducing RF.
