In my 23' Safari there are 2 of the air vents for the drains. One is accessible through the rear storage, just unscrews like a light bulb. The other is for the bath vanity. That one also unscrews but there is less than a half-inch clearance between it and the vanity table. I can unscrew it but then it reaches the vanity and that's it.
The sink J pipe comes to a T. One way is down to the floor, the other up to the vent. I don't see any connections that can be loosened. Not much wiggle room in there.
I'm hoping someone has found an easy way to get this vent off without having to remove the entire vanity. Surely the AS folk wouldn't have engineered it so you have to take all of that out.