Long term Seneca

The wife and I are a couple years out from retiring, selling our house and going fulltime. The Seneca is at the top of my list of prospective rides due to its towing capacity, which we're going to need, but the wife is worried. Diesel fumes make her physically sick, mostly associated with buses and trains she's ridden on, and it gets worse the longer she's exposed.

I'm not expecting a straight answer from a salesperson on this topic so I thought I'd ask: does anybody have any thoughts on how apparent the diesel fumes are when a Seneca is rolling down the road? Is there a cab air filter that deals with this?