If you and your date like beer, check out Flagship. They make great beers and have a really nice taproom in which to drink them. If you're someone who likes a casual vibe on a first date this definitely fits the bill. Also highly recommended for weekend daytime meetups. Only bummer is they're closed on Mondays.
Eat
They don't serve food, but if the date's going well we'd recommend ordering a pizza (they encourage you to bring food in).
Sit
Pleantiful picnic table seating.