You might try suggesting it to the staff of the venue you are hoping for him to play at. I have done that a couple of times and it has worked out. Of course, the final say is on Paul's end.
Yes, it may pay off to contact venue PR staff. I'd like to think ( but modesty prevents me...HAHAHA...along with probably many others with the same request) I helped get Paul to finally play Lambeau by starting the ball rolling in contacting the Packers a few years ago and opening a dialogue. In this intstance I actually was contacted back by the Director of PR for the Packers so who knows...Maybe Paul was already on their wishlist at that time.
So, in short...No one person can influence the choice of a tour stop but, if enough people express interst and are persistant, who knows?