I'm sorry no one answered your query.
I feel as if there must be nice places to sit outdoors in the Nperville area, but you probably already know them, being nearby. Maybe look at LAZ's list?
If you could stop by Glenview on your way down from the beaches, I just read in the Herald entertainment section that Cafe Lucci has a single table outside. They have very good food, wine and old-school service, great for a romantic evening. I would call (847-729-2268) to see about this outdoor table thing, though. I was there last week and can't imagine where it was.
Anyway, Happy Anniversary! At least you got decent weather for your outing.