I've heard these questions a few times from folk. I always suggest that, if the aircraft was equipped, the best thing possible would be for a Captain of that type (preferably TRE!) to go to the appropriate control centre and be given a headset to plug-in next to the controller. As the controller clears away other aircraft leaving just yourself and the TRE/Captain etc on the frequency the Captain would be able to explain which buttons to press for the autopilot, whilst the controllers find the closest airfield at which you'd be able to do an ILS autoland.
Manual flying? Forget it! Unless it was fly-by-wire you'd more than likely overcontrol and make a right good royal arse up of it. No matter the number of flight simulator hours you have, I doubt you'd be able to quickly adapt to the bizarre characteristics of whichever aircraft you find yourself having to manually fly!