Probably you do not go often over 50 meter pylon/trellis (ehm... put the right word for english here...)rextended the way to do this is reserve one ethernet port on the router with its own subnet and not on any bridge with admin access on the input chain so as to be able to gracefully recover from a config screwup. I do this with my main router AND every capac - I basiclly use eth2 on each capac as a secondary input mechanism not on the bridge of the Capac but able to access the capac.
Saved my bacon many a time.