Last year in New York it was about a 3 hour wait Sunday and 3.5 hour wait Monday so when you got on line you were aiming for the next group.
From looking at this list I am very surprised there are no Cardinals Hall of Famers there I would have guessed Red Schoendienst, Lou Brock or possibly Bob Gibson would participate one day but no dice.
Also last year on Monday (I think) was just so much better, they had a huge turnout as Gwynn + Gossage were paired together and Molitor + Feller + Fingers were also paired in the earlier session.
My tip for the fanfest would be to push the envelope and attempt to get more than one done. Gossage did 2 per and so did Aparicio, Fingers and Perry. Put one photo under the other if you do photos and you'll get it done. Gwynn was strictly 1 per and so was Molitor and Feller (surprising). The MLB people pay attention but you can work around it if you are not obvious.
Also they have the MLB authenticators there. I can't begin to tell you how little they like that job by the sad looks on their faces. YOU BETTER BE SURE they don't smudge your ball when they put that sticker on. Trust me on this, they don't care, and I saw alot of people getting pissed leaving the table due to the handling of their item (mostly baseballs).
If anyone is going they should also look into the XM radio booth I saw Jack McDowell and Jeff Nelson doing interviews there in a 1 hour period and were easily gettable. Not great names but if you don't want to wait 3 hours for Andy Benes and Jack Clark you'll get something. As far as those fan exhibitions, they usher those guys in and out and there is no graphing them. Last year it was Ripken, Jeter, etc big names but impossible.
Bottom line is find out where the MLB Gala is and you'll rack and spend no time in line (if where they enter is accessable)