How lucky for you to have such great resources at your disposal! I don't know what sort of writing you're doing or interested in doing. What I find helpful is to identify the people I want to hear and then go where they are. However, I have to say in favor of the Big Sur conference--I know some of the faculty and writers who've attended, and I have heard nothing but good things about it. So if you can, go to more than one event! And be sure to come to LA in August for nationals.
I just signed up for the Backspace Writers conference in NYC. A ton of the top YA Agents will be there. The first day is a query/first pages workshop, with the agents! check out the site below.