A CRV would be a one-use vehicle
Since a Crew Rescue Vehicle would only need to make a single reentry, you wouldn't need to use a reusable heat shield. So long as it didn't interfere with the aerodynamics or flight controls, you could probably get away with an ablative shield like the ones used on space capsules. I don't necessarily like the idea of tiles on a vehicle designed to be in orbit for a year at a time due to the thousands of thermal cycles (16 a day) it'd go through. I'd be concerned all those heating and cooling cycles could loosen the adhesive.