You're right that KSP physics would make it a bit easier than in real life. Even with FAR aerodynamics and Deadly re-entry it would probably be somewhat possible.
But Kerbal Space Program has very crude instruments and controls (especially when using the keyboard). It is very difficult to fly any kind of aircraft let alone gliders.
Perhaps using the built-in flight assists in FAR to maintain a steady pitch trim you could try to make it. But you'd still need to understand the best glide airspeed and other aerodynamic characteristics of the craft to make a deadstick landing.
It might be possible but extremely difficult to pull off an RTLS abort maneuver in KSP.
The hardest part of RTLS and the part that would result in infinite internet argument if they ever tried it, is if nothing goes wrong there's no purpose for it other than seeing if it works, and if anything goes wrong it probably won't work. APU failure. Control system failure. Total computer crash. Total electrical system failure. Exploding main engine takes out the back 15 feet of the shuttle. Engine gimble hydraulics jams one engine full one direction, maybe damaging the other engine nozzles by smooshing into them. Window blows out, probably taking out the deck crew but maybe the guys below survive. Back when the shuttle was in the commercial space truck biz, one of the boost stages in the cargo bay ignites (well that probably takes out the whole ship, how about the vibration of launch causes a short circuit that causes an electrical fire or propellant breach that damages stuff passing thru the bay, like electrical power and control lines.)
