You dont need to get a torque wrench in there. You dont need to get a shifter in there.
A long RING spanner will do the job. Or a socket and a medium extension will also do the job. You want to do them up as *tight* as you can. They're brakes, and the amount of torque you can apply by hand with or without a torque wrench is going to be the same. So do them up as tight as you can physically get them and then walk away. (And when i use the caveat of "as tight as you can get them" i do not mean if you can only feel like you can manage a quarter turn off when the bolt finishes being finger tight.)
Hang off it with all your bodyweight. Put loctite on there too for extra piece of mind if you want. The suspension doesnt need to come out to do brakes and if you're doing that, you're doing it wrong.
/thread.