What do you recommend up by Museum Mile? I have reservations at Atlantic Grill but I don't know anything about it. The other challenging factor is that we're going to the free admission night on June 8, and I don't feel like walking up all over the place too dressed up. So any ideas? Or will there be tons of street food carts up there for the event that would be a better choice? (That brings up the other challenge, finding a place that opens at 5 or earlier so I don't miss out on free museum time.)
Second question, please rate these in order of must-do to meh (or at least "you could skip and not cry yourself to sleep that you missed it"):
Craftbar, Gramercy Tavern, Jean-Georges Nougatine, Les Halles (but remember Monday is 1/2 priced wine!)
BONUS: I am out of my mind for thinking I can get from Manhattan to Prospect Park by in 30 minutes by train?

Re: Two restaurant related questions
I have not dined at Craftbar or Gramercy Tavern, but Les Halles and Jean-Georges Nougatine are not anywhere close to on the same page imo. They're completely different restaurants so it would be very hard to rate them against each other. Jean-Georges is "fine dining" while Les Halles is delicious food but in a much more laid back atmosphere. I personally prefer Les Halles but I'm much more of a casual person when it comes to eating out (and I love steak-frites!) My in laws took us (and all of my sils and their significant others) to Jean-Georges as a holiday "present" last year. It was lovely but it took 3 hours to eat. There are many different courses.
I don't know where in Manhattan you're coming from but I would have to guess that it would take you longer than 30 minutes. It takes me about 45 minutes to get from Cobble Hill to midtown. However I take the F train which is a slow train so like Liza said, if you take the Q train it may be doable.
"As of page 2 this might be the most boring argument ever. It's making me long for Rape Day." - Mouse