I'm not sure this will help your apps find your files but your best bet is to make a clone. I think Carbon Copy Cloner will let you do a basic clone without having to buy it, and there's also SuperDuper! and ChronoSync, both of which are also excellent and (all three are worth buying and are not expensive). I'm about to rush out the door so I haven't researched it but any of those apps will make an identical clone for you. Not certain that the OS will know whether or not it's not the same drive though, not without checking, which I can do later today.