Mostly just make sure parts with steel -- the chain, if nothing else -- are dry and lubed.

I always carry some plastic grocery store bags wadde dup in my rack trunk. They're very handy for things like covering your shoes in a sudden rainstorm, or covering your open seatpost during the day. Or putting wet clothes in. Or whatever.

Plastic bags. Gaffer's tape (or duct tape). Plastic zip ties. Wire. The basic emergency kit.

RichC