I like the idea of asking the Subaru sales-folk this question. That company does a good job w/their dog-car commercials, so more likely than not they’ll be able to offer some advice. The golden retriever male-dog who eyes a sexy poodle which makes his wife-dog jealous and angry is my favorite of those commercials.
It’s hard to predict whether a dog will go up stairs or ramps. One thing is nearly certain, if you act like you want them to, they won’t … lol .