I can't speak for Grey Ghost, but my own experience is that you will mostly need to ask stores to put in an order these days. Fudge has been out for decades now and print releases are infrequent to say the least, so shops tend to allocate their shelf space to more recent products.

You might try Shop on the Borderlands and Spirit Games, which I know occasionally carry one or two items in the range, but other than that you're looking at special orders at your nearest hobby shop, or eBay.