[Raider]

There are several people who run trains outside. I would suggest keeping the transformer, controller, stock and any cardboard models inside when not running tho

As for the power feeds, it is normal to have to put a feed on each section of track as the fishplates can tend to become loose outside and so you will get dead sections of track.

Not put an OO layout outside myself, but I have seen a some on the net.

HTH

Chris