Is there any way to get a pet into a 3rd story apartment accessible only by ladder?

If this were Conan Exiles, I would yes there is a way to move pets. In Conan Exiles, you simply click on a pet or pets and place them in another spot. But this is Sims 4 and not Conan Exiles, I don't know how you can if a ladder is the only access the 3rd floor. What you might want to do is do a google search for a Sims 4 mod that will allow you to live drag a pet to another location.