I think Murphy's Stunt Double was indicating that she would be in Phoenix in June, not Jim, thus missing the signing. For MSD, if you are a Laurell K. Hamilton fan, and in Phoenix on June 5th, The Poisoned Pen will be hosting a talk and signing by her at the Scottsdale Public Library. That one you do have to buy a book.
http://www.poisonedpen.com/event-calendar/laurell-k-hamiltonAs for Jim's signing, they will likely be doing it ticketed for the line, and the ticket you get when you buy the book. Those that don't buy a book there are at the end of the line. I'll see if I can find out when they will start doing the tickets. They usually don't limit copies signed, but if you have multiples of old books, they would certainly prefer you buy the new book from them.
The stairs on the back side are for the upper level, not the book store. Parking is somewhat limited at the store, but you can park along the side streets there. For those of you who were there last year, they have expanded the size of the store, but it will likely still be packed since last year the fans were split between the Poisoned Pen and the Arizona Book Festival for the most part.
Lee Whiteside