Opinions about Vendys on Gov. Island this Saturday (the 25th)?
This is the first time the Vendys are on governors island so no one will have the experience you are asking for. That being said, the line management at the Vendys has always been good. Some waiting is to be expected, but nothing extraordinary--espeically considering the number of trucks/carts this year. I would say that the biggest line issue would be for the ferrys. Just get there early and you will be fine.
I've been to Governor's Island for a different food event this summer, Meatopia. It's a lot of rolling hills and grassy areas to walk around in. Not much for seating, unless the people running the Vendy's are planning to provide seats (I believe that would be for the VIPs?)
I've spoken to Doug of The Big Gay Ice Cream Truck a few days ago and he does hope people who are attending to go there early. Food will run out if you're heading out toward the afternoon. Or in his case, his ice cream machine would overheat and won't produce soft serve properly.
Hope you'll have fun.
The Big Gay Ice Cream Truck said on Twitter earlier today there are expected to be 1200 guests. "1200 guests in that time frame is about 75% more than we safely promise serving."
So I'd try to be there right when they open and perhaps with multiple people so you can divide and conquer?