(Here's a concise defintion of "mundane SF.")
So, if your SF can't have faster-than-light travel or communications, aliens, time travel, alternate universes, immortality, telepathy, or any other type of speculative (unproven) ideas, what do you have left? Mundane-ness! So let's mundane some famous novels. Here are my offerings:
Ender's Computer Game
Less Than Human
A Fire upon the Shallows
What would you add? I assume you also can't have artificial intelligence, re-created dinosaurs, technological singularities, mind uploads, or anti-gravity. Dark matter is iffy, I would bet. Let's mundane-ize SF!