I've been going to the Arizona Antique and Classic Motorcycle Show for about 20 of it's 23 years. It's nearly always been an excellent show with interesting bikes and interesting people in attendance not to mention a pretty good swap meet will all manner of interesting bike stuff set out for your browsing pleasure.
I highly recommend that you set aside April 1 to attend the event as it will be a day well spent. The event isn't as big as some events in other states but the turn out of machinery for the Arizona event put on by Arizona Antique and Classic Motorcycle Enthusiasts' organization really is extensive in the eras and types of bikes that show up. A good turn out of spectators means that the event is sure to grow each year so support the event and have a great time in the process. I will be there taking photos so look for the guy in the Bultaco hat with a Nikon 8800 stuck to his face and say "hi."