The book I have is called Back Country Adventures Northern California, one of the biggest ghost towns that is in it looks like the Bodie Ghost Town Trail. Its a little further south from down by 108 and almost all the way to the Nevada boarder by mono lake, but still looks pretty cool. The book says it takes 3hrs to do. If you google search it you can probable find more info then this book says.
As for trails that are closer, the book has a ton but all that remains of the towns are maybe a building here or there, cool little things but nothing like a full scale ghost town. I havnt done Bodie yet, I have it on my list of todo trails sometime this summer/fall.