Thanks. I went through the earlier thread and the one post that meant the most was the one where someone said do not let the transmitter get wet. I was not sure on that but now I know.
If I can get a decent signal in testing from the rear of the camper with the transmitter outside near the roof I think I'm going to try to make a small plexiglass case with the transmitter mounted in it that I can seal up and mount it where I get the best picture. If not I will revert to inside mounting on the transmitter and take what I can get. I do like the idea of it being on all the time versus only in reverse though and think I might try to hook it up that way initially.