Gender shouldn't have anything to do with a transmission temp gauge. :B
Your dealer might install one but they will likely stall you or make it cost more than it is worth. Sometimes they get it their head that they can't to anything because it will void the warranty. I wouldn't let a RV place anywhere near the chassis, most are above their head just changing the air in the tires.
Unless your are planning to really give your rig it a workout I wouldn't bother with it. Maybe increase the drain interval for the trans. Scangage might be an option.