For what it is worth, I use a Swift Hitch to hook up my TT. It has a magnetic (or can be screwed on) and probably has the range, but I'm not sure it would be good for your purpose because it uses a hand-held receiver (or can be velcroed to the dash). I saw camping world had a similar unit on sale for abut 150. The receiver comes with a cord that can be plugged into another monitor. I'm not sure about the charge life because I never have it on more than five or ten minutes. The units are rechargeable.