Grossmont Trolley Center

Unfortunately, there's no real way you're getting on top of that Trolley, not unless you have magical jumping abilities... which you do not. Besides, there's no cover from Humans. All you can hope for is to sneak some of this center's shade when there aren't any Humans around.
You can get here via stairs from the Grossmont Shopping Center, but the stairs are made of crickety old wood and give both Humans and cats an uneasy feeling when using them.
What are the odds of them ever collapsing under ones' feed? Low. But that doesn't mean it won't happen someday.
You can make the small steep hills that the Trolley's line cuts through your home, though. No cats, or dogs even, have seemed to claim it yet. They're just about big enough for a clutter of cats.