I saw this in the 10-minute tech section of Trailer Life Magazine. Someone took a short length of plastic pvc pipe of the right diameter and cut notches in one end so it would engage the vent's knob, which is six-sided and star-shaped.
My wife has same problem in our fifth-wheel bathroom. I have been intending to measure our own knob and make one for myself, but I have not done it yet. I need to get busy and do it before our first outing in April.
What I have done is to put a switch for the vent's fan so that my wife can operate the fan. That was easy -- I ran the fan's wire through a switch that is conveniently located on the bathroom wall, then back to the fan.
