Winter weather without winterizing?

Yeah, Seattle area here. I was told by people from east of the mountains that winterizing is critical but temps don't get as cold on the west side. I currently have water in the fresh water tank and the gray/black are empty. I could drain the fresh tank and blow it out, but since I want to use it in the near future seems like adding a little heat would be more than enough for our weather. But I'm new to TC's so I want to make sure I don't cause needless damage.

Also, is there any concern that should be paid to outside shower head? I beleive I drained it last use but is that sufficient so long as we don't get a sustained freeze?